ubsan shift fixes

src/core/SkScan_Path.cpp

 /*
  * Copyright 2006 The Android Open Source Project
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkScanPriv.h"
 #include "SkBlitter.h"
 #include "SkEdge.h"
@@ skipping 432 matching lines @@
     headEdge.fX = SK_MinS32;
     edge->fPrev = &headEdge;
 
     tailEdge.fPrev = last;
     tailEdge.fNext = nullptr;
     tailEdge.fFirstY = kEDGE_TAIL_Y;
     last->fNext = &tailEdge;
 
     // now edge is the head of the sorted linklist
 
-    start_y <<= shiftEdgesUp;
-    stop_y <<= shiftEdgesUp;
+    start_y = SkLeftShift(start_y, shiftEdgesUp);
+    stop_y = SkLeftShift(stop_y, shiftEdgesUp);
     if (clipRect && start_y < clipRect->fTop) {
         start_y = clipRect->fTop;
     }
     if (clipRect && stop_y > clipRect->fBottom) {
         stop_y = clipRect->fBottom;
     }
 
     InverseBlitter  ib;
     PrePostProc     proc = nullptr;
 
@@ skipping 235 matching lines @@
         clipRgn = &wrap.getRgn();
         blitter = wrap.getBlitter();
     }
 
     SkScanClipper clipper(blitter, clipRgn, ir);
     blitter = clipper.getBlitter();
     if (blitter) {
         sk_fill_triangle(pts, clipper.getClipRect(), blitter, ir);
     }
 }