reduce exposure of SK_SUPPORT_LEGACY_TILED_BITMAPS to not replace repeats yet

A large swath of skps slowed down ~5-6x, likely because of repeat_repeat tiling
slowdowns. This CL reduces our exposure to keep those in legacy mode for now.

Bug: skia:
Change-Id: I16d03c01fe8c14a8b9b6a1a9a0c5f31f8d616b4a
Reviewed-on: https://skia-review.googlesource.com/20694
Reviewed-by: Mike Klein <mtklein@chromium.org>
Commit-Queue: Mike Reed <reed@google.com>

src/shaders/SkImageShader.cpp

@@ -54,7 +54,7 @@ bool SkImageShader::IsRasterPipelineOnly(SkColorType ct, SkShader::TileMode tx,
     if (ct != kN32_SkColorType) {
         return true;
     }
-    if (tx != SkShader::kClamp_TileMode || ty != SkShader::kClamp_TileMode) {
+    if (tx != ty) {
         return true;
     }
 #endif