On Windows, the basename is used to determine the name of the PDB
file. So for a project called myproject, we will create myproject.dll
and myproject.exe, both of which will have myproject.pdb. This is
a file collision. Instead, append `_test`, similar to the C# template.
Fixes AllPlatformTest.test_templates on MSVC. This became a hard error
when we started listing PDBs in the implicit outputs list of ninja
targets.
Do the same for a test that was making the same mistake.
Daniel Mensinger