Fix PATH when running MSVC for ARM64 target

The ARM64 MSVC toolchain only includes some of the executables. Other
functionality is in DLLs that are located in the host (x64) toolchain
directory. Hopefully MS fixes this at some point.

Bug: skia:8569
Change-Id: I1a96c63c9bdcf656eb2d84b81636d54304766c20
Reviewed-on: https://skia-review.googlesource.com/c/175821
Commit-Queue: Brian Osman <brianosman@google.com>
Commit-Queue: Mike Klein <mtklein@google.com>
Reviewed-by: Mike Klein <mtklein@google.com>
2 files changed