Remove SkTextBlobRunIterator.h from gni

Change-Id: I62d43c19899b4cccca9bf285a06de70a969fbe9f
Reviewed-on: https://skia-review.googlesource.com/144024
Commit-Queue: Herb Derby <herb@google.com>
Commit-Queue: Florin Malita <fmalita@chromium.org>
Auto-Submit: Herb Derby <herb@google.com>
Reviewed-by: Florin Malita <fmalita@chromium.org>
diff --git a/gn/core.gni b/gn/core.gni
index 0c22304..d28c50d 100644
--- a/gn/core.gni
+++ b/gn/core.gni
@@ -314,7 +314,6 @@
   "$_src/core/SkTDPQueue.h",
   "$_src/core/SkTDynamicHash.h",
   "$_src/core/SkTextBlob.cpp",
-  "$_src/core/SkTextBlobRunIterator.h",
   "$_src/core/SkTextFormatParams.h",
   "$_src/core/SkTextMapStateProc.h",
   "$_src/core/SkTextToPathIter.h",