Check for sync extensions only on correct context types

GL_APPLE_sync is ES only. GL_ARB_sync is not ES.

Change-Id: If595c01ec9a878a4d73862fa4ba79a76f1173d77
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/293574
Reviewed-by: Brian Osman <brianosman@google.com>
Commit-Queue: Brian Salomon <bsalomon@google.com>
1 file changed