Fix path handling in prefix inspections (#35318)

At least with ZSH, prefix inspections containing `./bin` result in a
`$PREFIX/./bin` and result in strange `$PATH` handling.

I.e., `module load git` will prepend `/path/to/git/./bin`, `which git`
will find the right executable, but `git --version` will print the
system one. Normalize the relative path to avoid this behavior.

See also spack/spack#31867.

lib/spack/spack/util/environment.py

@@ -912,7 +912,7 @@ def inspect_path(root, inspections, exclude=None):
     env = EnvironmentModifications()
     # Inspect the prefix to check for the existence of common directories
     for relative_path, variables in inspections.items():
-        expected = os.path.join(root, relative_path)
+        expected = os.path.join(root, os.path.normpath(relative_path))
 
         if os.path.isdir(expected) and not exclude(expected):
             for variable in variables: