Remove support for deprecated kDontClipToLayer_SaveLayerFlag

This removes the conditional behavior based on #defines, and the private
flag definitions. It removes GMs and updates tests that tested the
feature. Follow-up CLs will go through and simplify the internals of
SkCanvas to take advantage of this support removal.

Bug: skia:10986
Change-Id: Id42c9e7d134dd06507fabf6577e7872942ef9077
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/339988
Commit-Queue: Michael Ludwig <michaelludwig@google.com>
Reviewed-by: Mike Reed <reed@google.com>
diff --git a/RELEASE_NOTES.txt b/RELEASE_NOTES.txt
index c2b4bbd..b853be4 100644
--- a/RELEASE_NOTES.txt
+++ b/RELEASE_NOTES.txt
@@ -6,6 +6,9 @@
 
 Milestone 89
 ------------
+  * Remove support for deprecated kDontClipToLayer_SaveLayerFlag in SkCanvas::SaveLayerRec
+    https://review.skia.org/339988
+
   * Expose more info in SkCodec::FrameInfo
     https://review.skia.org/339857