Switch clang to r353983

Bug: 126457671
Bug: 123638879
Bug: 128878287
Test: go/clang-r353983-testing
Change-Id: I7f16e68f0f521ff55587084932d175b704e452c9
diff --git a/cc/config/clang.go b/cc/config/clang.go
index 6a1c736..a57bbf8 100644
--- a/cc/config/clang.go
+++ b/cc/config/clang.go
@@ -174,6 +174,10 @@
 
 		// Disable this warning because we don't care about behavior with older compilers.
 		"-Wno-return-std-move-in-c++11",
+
+		// Disable -Wstring-plus-int until the instances detected by this new warning is
+		// fixed.
+		"-Wno-string-plus-int",
 	}, " "))
 
 	// Extra cflags for projects under external/ directory