[PM] Try to work-around what appears to be an MSVC SFINAE issue with

r279217 where it fails to select the path that other compilers select.

The workaround won't be as careful to produce an error when an analysis
result is incorrect, but we can rely on non-MSVC builds to catch such
errors it seems and MSVC doesn't seem to support the alternative
techniques.

Hoping this brings the windows bots back to life. If not, will have to
revert all of this.

llvm-svn: 279225