Refactoring determine_binary_type to fix some bugs

Four of the first 12 cases in the new unit test previously failed (the
logic to reduce from vector to scalar type coercion didn't test the
reverse order, so (half * float4) would only test if (half * float) was
possible going right-to-left.

Also, the matrix multiplication logic was missing a check when doing *=,
allowing things like (matrix *= vector) to compile (then fail later in
GL, etc.)

Finally, we were never checking if the op was valid for vectors when
doing the vector/scalar combination. Added test cases to
BinaryTypeMismatch that previously failed, and now work.

Change-Id: I1e2709e3ba4df31f9300672189826151eabe017a
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/315964
Commit-Queue: Brian Osman <brianosman@google.com>
Reviewed-by: John Stiles <johnstiles@google.com>
2 files changed