Make GrClipStack, GrClipStackClip, and GrReducedClip OGA-only

GrStencilClip and GrStencilMaskHelper just come along for the ride

Bug: skia:11837
Change-Id: I7cfa2dd620b7457e6b6be4abf91b1ecd415d9b73
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/417680
Commit-Queue: Robert Phillips <robertphillips@google.com>
Reviewed-by: Michael Ludwig <michaelludwig@google.com>
diff --git a/gn/tests.gni b/gn/tests.gni
index f86796b..b339806 100644
--- a/gn/tests.gni
+++ b/gn/tests.gni
@@ -100,7 +100,6 @@
   "$_tests/GrAHardwareBufferTest.cpp",
   "$_tests/GrBlockAllocatorTest.cpp",
   "$_tests/GrCCPRTest.cpp",
-  "$_tests/GrClipStackTest.cpp",
   "$_tests/GrContextAbandonTest.cpp",
   "$_tests/GrContextFactoryTest.cpp",
   "$_tests/GrContextOOM.cpp",
@@ -427,3 +426,7 @@
   "$_tests/PathOpsTypesTest.cpp",
   "$_tests/WangsFormulaTest.cpp",
 ]
+
+oga_tests_sources = [ "$_tests/GrClipStackTest.cpp" ]
+
+tests_sources += oga_tests_sources