Revert "Remove flag for misc sampling apis"

This reverts commit 3f31f3027f.

Reason for revert: breaking g3

Original change's description:
> Remove flag for misc sampling apis
>
> Change-Id: Ia1f2d94000b6929883face241d1786de9d65e22a
> Reviewed-on: https://skia-review.googlesource.com/c/skia/+/358736
> Reviewed-by: Mike Reed <reed@google.com>
> Commit-Queue: Mike Reed <reed@google.com>

TBR=reed@google.com

Change-Id: I487b99eabbf54f680b8f4cac4343ba74cae90d31
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/359176
Reviewed-by: Mike Reed <reed@google.com>

gn/flutter_defines.gni

@@ -17,7 +17,6 @@ flutter_defines = [
   # Staging
   "SK_SUPPORT_LEGACY_ADJUSTHQHEURISTIC",
   "SK_SUPPORT_LEGACY_IMPLICIT_FILTERQUALITY",
-  "SK_SUPPORT_LEGACY_PAINT_QUALITY_APIS",
 
   # Fast low-precision software rendering isn't a priority for Flutter.
   "SK_DISABLE_LEGACY_SHADERCONTEXT",

include/core/SkCanvas.h

@@ -40,6 +40,10 @@
 
 #define SK_SUPPORT_LEGACY_DRAWIMAGE_NOSAMPLING
 
+#ifndef SK_SUPPORT_LEGACY_PAINT_QUALITY_APIS
+#define SK_SUPPORT_LEGACY_PAINT_QUALITY_APIS
+#endif
+
 class GrBackendRenderTarget;
 class GrRecordingContext;
 class GrSurfaceDrawContext;