Remove win_toolchain name substitution
Remove win_toolchain name substitution

Skia's win_toolchain asset no longer includes extraneous directories, so
we can use a descriptive path name.

See: https://skia-review.googlesource.com/c/skia/+/176973
and: https://skia-review.googlesource.com/c/skia/+/176968

Bug: skia:
Change-Id: If1b94eb46168eead043ab59b6c7f29a789f45c29
Reviewed-on: https://skia-review.googlesource.com/c/176979
Commit-Queue: Eric Boren <0e499112533c8544f0505ea0d08394fb5ad7d8fa@google.com>
Reviewed-by: Eric Boren <0e499112533c8544f0505ea0d08394fb5ad7d8fa@google.com>

google/skia-buildbot,google/skia-buildbot,google/skia-buildbot,google/skia-buildbot,google/skia-buildbot,google/skia-buildbot,google/skia-buildbot,google/skia-buildbot