[lldb] Update the PDB tests to pass with the VS2019 toolset

The pdb lldb tests do not work correctly with both the VS2019 and VS2017 toolsets at the moment. This change updates several of the tests to work with both toolsets. Unfortunately, this makes the tests suboptimal for both toolsets, but we can update them to be better for VS2019 once we officially drop VS2017. This change is meant to bridge the gap until the update happens, so that the buildbots can work with either toolset.

Differential Revision: https://reviews.llvm.org/D115482