GM: Allow ignored-tests.txt to list configs as well as tests (and combinations too)

expectations/gm/ignored-tests.txt

Index: expectations/gm/ignored-tests.txt
===================================================================
--- expectations/gm/ignored-tests.txt	(revision 11630)
+++ expectations/gm/ignored-tests.txt	(working copy)
@@ -1,5 +1,5 @@
-# Failures of any GM tests listed in this file will be ignored, as if they
-# had been marked "ignore-failure": true in the per-builder
+# Failures of any GM tests/configs listed in this file will be ignored, as if
+# they had been marked "ignore-failure": true in the per-builder
 # expected-results.json files.
 #
 # The idea is that, if you modify a GM test in such a way that you know it will
@@ -17,6 +17,12 @@
 # ('GM expectations: create tool to suppress failures until new baselines are
 # checked in')
 
-# EXAMPLE: (remove the first '#' on each line)
+# EXAMPLES: (remove the first '#' on each line)
+#
 ## Added by edisonn as part of https://codereview.chromium.org/23851037/
 #gradients
+#
+## Added by epoger as part of MADE-UP BUG
+## https://code.google.com/p/skia/issues/detail?id=123456 : ignoring failures on
+## gpu config of gradtext GM test
+#gradtext_gpu