Remove skia_core_defines

Two usages had been removed in
https://pdfium-review.googlesource.com/c/pdfium/+/96570
https://chromium-review.googlesource.com/c/chromium/src/+/3831118

Change-Id: I1606aa0ae8718378f58ea1ca8311b6c008d4d485
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/569317
Commit-Queue: Kevin Lubick <kjlubick@google.com>
Reviewed-by: Ben Wagner <bungeman@google.com>
1 file changed