Split up opLists (take 3)

Reland of: https://skia-review.googlesource.com/c/11581/ (Split up opLists)

https://skia-review.googlesource.com/c/13860/ (Make InstancedRendering more opList-splitting friendly) has landed so this should be good for another attempt.

TBR=egdaniel@google.com
Change-Id: I2a09729342bb035af3a16807c1895adbae432ade
Reviewed-on: https://skia-review.googlesource.com/14186
Reviewed-by: Robert Phillips <robertphillips@google.com>
Commit-Queue: Robert Phillips <robertphillips@google.com>
diff --git a/tests/SurfaceTest.cpp b/tests/SurfaceTest.cpp
index 1a03f15..b8092e4 100644
--- a/tests/SurfaceTest.cpp
+++ b/tests/SurfaceTest.cpp
@@ -914,6 +914,8 @@
     test_surface_creation_and_snapshot_with_color_space(reporter, "wrapped", f16Support,
                                                         wrappedSurfaceMaker);
 
+    context->flush();
+
     for (auto textureHandle : textureHandles) {
         context->getGpu()->deleteTestingOnlyBackendTexture(textureHandle);
     }