Fix crash when inverse() is passed a constant variable.

Optimization for inverse() uses some custom logic which neglected to
look up the value of a constant variable before assuming it was a
FloatLiteral; our tests were not exercising this case.

Change-Id: Idc8f2cc24f6a8df7234062f5f15e8c39a08457e5
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/440260
Commit-Queue: John Stiles <johnstiles@google.com>
Commit-Queue: Brian Osman <brianosman@google.com>
Auto-Submit: John Stiles <johnstiles@google.com>
Reviewed-by: Brian Osman <brianosman@google.com>
2 files changed