Genex: Revise RunCMake.GeneratorExpression PDB test cases

Use if(MSVC) as condition so it passes for Intel on Windows too.
Add expected stderr in success case to ensure it is empty.
Merge topic 'pdb-genex' into next

58e9f838 Genex: Revise RunCMake.GeneratorExpression PDB test cases
Genex: Simplify filesytem artifact code
Genex: Implement generator expressions for target PDB files.
Merge topic 'pdb-genex' into next

164aa9f1 Genex: Implement generator expressions for target PDB files.
028ad318 Genex: Simplify filesytem artifact code