32-bit PGO builds need to modify the PATH to find pgortXXX.dll. We were
doing this for Visual Studio 2013 (VC12) in 2 locations. We weren't
doing it for Visual Studio 2015. This resulted in a failure to launch
PGO instrumented executables because pgort140.dll could not be found.
This commit refactors the PATH munging to support Visual Studio 2015.
MozReview-Commit-ID: 4EKf8gjcNH6
--HG--
extra : rebase_source : 2772558b06202d26583401bc41e56da8c5a69ef4