Revert of Move gn _run target generation into test().

third_party/WebKit/Source/wtf/BUILD.gn

Index: third_party/WebKit/Source/wtf/BUILD.gn
diff --git a/third_party/WebKit/Source/wtf/BUILD.gn b/third_party/WebKit/Source/wtf/BUILD.gn
index b7cce42f23b32b1f6f31c441c2ff0cecfe70570c..09d9eff9dfc687959d61bc96bbcdc245eaeead8e 100644
--- a/third_party/WebKit/Source/wtf/BUILD.gn
+++ b/third_party/WebKit/Source/wtf/BUILD.gn
@@ -95,6 +95,15 @@
   }
 }
 
+# TODO(GYP): Delete this after we've converted everything to GN.
+# The _run targets exist only for compatibility w/ GYP.
+group("wtf_unittests_run") {
+  testonly = true
+  deps = [
+    ":wtf_unittests",
+  ]
+}
+
 test("wtf_unittests") {
   visibility = []  # Allow re-assignment of list.
   visibility = [ "*" ]