Enable -Wambiguous-reversed-operator

Bug: http://b/323152930
Bug: http://b/324323434

The ambiguity in frameworks/av/media/codec2 is resolved.

Test: build partner branch, and presubmit
Change-Id: Ie1aa0b6c965b1a9076333d7d25fd9f9664467a31
diff --git a/cc/config/global.go b/cc/config/global.go
index 613641f..d3c2658 100644
--- a/cc/config/global.go
+++ b/cc/config/global.go
@@ -302,8 +302,6 @@
 		// until then because it causes warnings in the _callers_, not the
 		// project itself.
 		"-Wno-deprecated-dynamic-exception-spec",
-		// http://b/324323434
-		"-Wno-ambiguous-reversed-operator",
 	}
 
 	noOverride64GlobalCflags = []string{}