Move tessellation shader files into a subdirectory

Also renames GrStrokeShader -> GrStrokeTessellationShader.

Bug: skia:10419
Change-Id: I75b09f794ef86a4cd8c467a1fd61cc87fe68091b
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/413756
Commit-Queue: Chris Dalton <csmartdalton@google.com>
Reviewed-by: Robert Phillips <robertphillips@google.com>
diff --git a/src/gpu/tessellate/GrPathStencilFillOp.h b/src/gpu/tessellate/GrPathStencilFillOp.h
index f31d416..c41d1fe 100644
--- a/src/gpu/tessellate/GrPathStencilFillOp.h
+++ b/src/gpu/tessellate/GrPathStencilFillOp.h
@@ -10,7 +10,7 @@
 
 #include "src/gpu/ops/GrDrawOp.h"
 #include "src/gpu/tessellate/GrTessellationPathRenderer.h"
-#include "src/gpu/tessellate/GrTessellationShader.h"
+#include "src/gpu/tessellate/shaders/GrTessellationShader.h"
 
 class GrPathTessellator;