Bootstrap environment modules optimizing for generic architectures (#13105)

fixes #13073

Since #3206 was merged bootstrapping environment-modules was using the architecture of the current host or the best match supported by the default compiler. The former case is an issue since shell integration was looking for a spec targeted at the host microarchitecture.

1. Bootstrap an env modules targeted at generic architectures
2. Look for generic targets in shell integration scripts
3. Add a new entry in Travis to test shell integration

share/spack/qa/run-bootstrap-tests

@@ -0,0 +1,37 @@
+#!/bin/bash -e
+#
+# Copyright 2013-2019 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)
+
+#
+# Description:
+#     Checks that Spack shell integration with modules works correctly.
+#
+# Usage:
+#     run-bootstrap-tests
+#
+. "$(dirname $0)/setup.sh"
+check_dependencies ${coverage} git hg svn
+
+# Fetch the sources in a mirror, and add it to Spack
+mkdir -p ~/.mirror
+bin/spack mirror add travis ~/.mirror
+bin/spack mirror create -D -d ~/.mirror environment-modules~X
+
+
+# Move to root directory of Spack
+# Allows script to be run from anywhere
+cd "$SPACK_ROOT"
+
+# Print compiler information
+spack config get compilers
+
+# Run some build smoke tests, potentially with code coverage
+${coverage_run} bin/spack bootstrap
+
+# Check module integration
+. "share/spack/setup-env.sh"
+module av || exit 1
+spack load tcl || exit 1