Remove obsolete SK_IGNORE_ defines

In chronological order:

SK_IGNORE_THIN_STROKED_RECT_FIX   : https://codereview.chromium.org/18317003/
SK_IGNORE_64BIT_OPENGL_CHANGES    : https://codereview.chromium.org/118533003/
SK_IGNORE_FAST_RRECT_BLUR         : https://codereview.chromium.org/189663012/
SK_IGNORE_MATRIX_IMAGE_FILTER_FIX : https://skia-review.googlesource.com/c/skia/+/127125/

Bug: skia:
Change-Id: I082ee9b0636f8523476b0271677f46b274f1ce97
Reviewed-on: https://skia-review.googlesource.com/c/170721
Reviewed-by: Brian Salomon <bsalomon@google.com>
Commit-Queue: Brian Osman <brianosman@google.com>
4 files changed