Add GYP target for sk_tool_utils.* component.

gyp/tests.gypi

Index: gyp/tests.gypi
diff --git a/gyp/tests.gypi b/gyp/tests.gypi
index 2a7dddd4ff02882b6d7196d64694533254be7dc7..1f619cfbf63596bb280804559b2ab79bb9cf6761 100644
--- a/gyp/tests.gypi
+++ b/gyp/tests.gypi
@@ -21,6 +21,7 @@
     'flags.gyp:flags',
     'pdf.gyp:pdf',
     'resources.gyp:resources',
+    'sk_tool_utils.gyp:sk_tool_utils',
     'skia_lib.gyp:skia_lib',
     'tools.gyp:picture_utils',
   ],
@@ -197,7 +198,5 @@
 
     '../tests/TDStackNesterTest.cpp',
     '../experimental/PdfViewer/src/SkTDStackNester.h',
-
-    '../tools/sk_tool_utils.cpp',
   ],
 }