Revert "Revert "Extend SkCanvas matrix stack to be 4x4, but with (basically) the same public API.""

The reason for the assert was breaking an assert, that if the CTM was scale/translate, that after
a preTranslate, it should still be that.

This is true... unless the new translate values are non-finite. In that case, we might turn a zero
into a NaN, (0 * non_finite --> nan), so we either have to require finite args (which we don't
at the moment) or we can't make this assert. This re-land removes that assert.

This reverts commit 268ed57d71e7aa7230d0c1a5722cf84a65f43e61.

Change-Id: I3c48a0aa17649351a246c1fbab5449f2d59aaf84
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/263023
Commit-Queue: Mike Reed <reed@google.com>
Commit-Queue: Brian Osman <brianosman@google.com>
Auto-Submit: Mike Reed <reed@google.com>
Reviewed-by: Brian Osman <brianosman@google.com>
12 files changed