Remove staging flag for raster clip aa disabling

Bug: skia:7998, chromium:1240718
Change-Id: I32a7806fca53db5c120460dcf5738cab84662926
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/441542
Commit-Queue: Michael Ludwig <michaelludwig@google.com>
Commit-Queue: Florin Malita <fmalita@google.com>
Auto-Submit: Michael Ludwig <michaelludwig@google.com>
Reviewed-by: Florin Malita <fmalita@google.com>
Reviewed-by: Robert Phillips <robertphillips@google.com>

src/core/SkRasterClipStack.h

@@ -67,12 +67,7 @@ public:
     SkRasterClipStack(int width, int height)
         : fStack(fStorage, sizeof(fStorage))
         , fRootBounds(SkIRect::MakeWH(width, height))
-#if !defined(SK_PRESERVE_RC_AA)
-        , fDisableAA(SkScan::DowngradeClipAA(fRootBounds))
-#else
-        , fDisableAA(false)
-#endif
-    {
+        , fDisableAA(SkScan::DowngradeClipAA(fRootBounds)) {
         Rec& rec = fStack.push();
         rec.fRC.setRect(fRootBounds);
         rec.fDeferredCount = 0;