concretizer: enable hash reuse with full hash

With the original DAG hash, we did not store build dependencies in the database, but
with the full DAG hash, we do. Previously, we'd never tell the concretizer about build
dependencies of things used by hash, because we never had them. Now, we have to avoid
telling the concretizer about them, or they'll unnecessarily constrain build
dependencies for new concretizations.

- [x] Make database track all dependencies included in the `dag_hash`
- [x] Modify spec_clauses so that build dependency information is optional
      and off by default.
- [x] `spack diff` asks `spec_clauses` for build dependencies for completeness
- [x] Modify `concretize.lp` so that reuse optimization doesn't affect fresh
      installations.
- [x] Modify concretizer setup so that it does *not* prioritize installed versions
      over package versions. We don't need this with reuse, so they're low priority.
- [x] Fix `test_installed_deps` for full hash and new concretizer (does not work
      for old concretizer with full hash -- leave this for later if we need it)
- [x] Move `test_installed_deps` mock packages to `builtin.mock` for easier debugging
      with `spack -m`.
- [x] Fix `test_reuse_installed_packages_when_package_def_changes` for full hash

var/spack/repos/builtin.mock/packages/installed-deps-a/package.py

@@ -0,0 +1,26 @@
+# Copyright 2013-2022 Lawrence Livermore National Security, LLC and other
+# Spack Project Developers. See the top-level COPYRIGHT file for details.
+#
+# SPDX-License-Identifier: (Apache-2.0 OR MIT)
+
+from spack import *
+
+
+class InstalledDepsA(Package):
+    """Used by test_installed_deps test case."""
+    #     a
+    #    / \
+    #   b   c   b --> d build/link
+    #   |\ /|   b --> e build/link
+    #   |/ \|   c --> d build
+    #   d   e   c --> e build/link
+
+    homepage = "http://www.example.com"
+    url      = "http://www.example.com/a-1.0.tar.gz"
+
+    version("1", "0123456789abcdef0123456789abcdef")
+    version("2", "abcdef0123456789abcdef0123456789")
+    version("3", "def0123456789abcdef0123456789abc")
+
+    depends_on("installed-deps-b", type=("build", "link"))
+    depends_on("installed-deps-c", type=("build", "link"))

var/spack/repos/builtin.mock/packages/installed-deps-b/package.py

@@ -0,0 +1,26 @@
+# Copyright 2013-2022 Lawrence Livermore National Security, LLC and other
+# Spack Project Developers. See the top-level COPYRIGHT file for details.
+#
+# SPDX-License-Identifier: (Apache-2.0 OR MIT)
+
+from spack import *
+
+
+class InstalledDepsB(Package):
+    """Used by test_installed_deps test case."""
+    #     a
+    #    / \
+    #   b   c   b --> d build/link
+    #   |\ /|   b --> e build/link
+    #   |/ \|   c --> d build
+    #   d   e   c --> e build/link
+
+    homepage = "http://www.example.com"
+    url      = "http://www.example.com/b-1.0.tar.gz"
+
+    version("1", "0123456789abcdef0123456789abcdef")
+    version("2", "abcdef0123456789abcdef0123456789")
+    version("3", "def0123456789abcdef0123456789abc")
+
+    depends_on("installed-deps-d", type=("build", "link"))
+    depends_on("installed-deps-e", type=("build", "link"))

var/spack/repos/builtin.mock/packages/installed-deps-c/package.py

@@ -0,0 +1,26 @@
+# Copyright 2013-2022 Lawrence Livermore National Security, LLC and other
+# Spack Project Developers. See the top-level COPYRIGHT file for details.
+#
+# SPDX-License-Identifier: (Apache-2.0 OR MIT)
+
+from spack import *
+
+
+class InstalledDepsC(Package):
+    """Used by test_installed_deps test case."""
+    #     a
+    #    / \
+    #   b   c   b --> d build/link
+    #   |\ /|   b --> e build/link
+    #   |/ \|   c --> d build
+    #   d   e   c --> e build/link
+
+    homepage = "http://www.example.com"
+    url      = "http://www.example.com/c-1.0.tar.gz"
+
+    version("1", "0123456789abcdef0123456789abcdef")
+    version("2", "abcdef0123456789abcdef0123456789")
+    version("3", "def0123456789abcdef0123456789abc")
+
+    depends_on("installed-deps-d@2", type="build")
+    depends_on("installed-deps-e@2", type=("build", "link"))

var/spack/repos/builtin.mock/packages/installed-deps-d/package.py

@@ -0,0 +1,23 @@
+# Copyright 2013-2022 Lawrence Livermore National Security, LLC and other
+# Spack Project Developers. See the top-level COPYRIGHT file for details.
+#
+# SPDX-License-Identifier: (Apache-2.0 OR MIT)
+
+from spack import *
+
+
+class InstalledDepsD(Package):
+    """Used by test_installed_deps test case."""
+    #     a
+    #    / \
+    #   b   c   b --> d build/link
+    #   |\ /|   b --> e build/link
+    #   |/ \|   c --> d build
+    #   d   e   c --> e build/link
+
+    homepage = "http://www.example.com"
+    url      = "http://www.example.com/d-1.0.tar.gz"
+
+    version("1", "0123456789abcdef0123456789abcdef")
+    version("2", "abcdef0123456789abcdef0123456789")
+    version("3", "def0123456789abcdef0123456789abc")

var/spack/repos/builtin.mock/packages/installed-deps-e/package.py

@@ -0,0 +1,23 @@
+# Copyright 2013-2022 Lawrence Livermore National Security, LLC and other
+# Spack Project Developers. See the top-level COPYRIGHT file for details.
+#
+# SPDX-License-Identifier: (Apache-2.0 OR MIT)
+
+from spack import *
+
+
+class InstalledDepsE(Package):
+    """Used by test_installed_deps test case."""
+    #     a
+    #    / \
+    #   b   c   b --> d build/link
+    #   |\ /|   b --> e build/link
+    #   |/ \|   c --> d build
+    #   d   e   c --> e build/link
+
+    homepage = "http://www.example.com"
+    url      = "http://www.example.com/e-1.0.tar.gz"
+
+    version("1", "0123456789abcdef0123456789abcdef")
+    version("2", "abcdef0123456789abcdef0123456789")
+    version("3", "def0123456789abcdef0123456789abc")