Make clang libTooling tools ignore all lto flags.

LLVM r275480 does not recognize flto flags, suppress the option in clang
libTooling tools for now.

Bug: 62839002

Test: mma

Change-Id: Ia9d80b46320e551a93dbff780405d8ff8ad73f35

cc/config/clang.go

@@ -66,7 +66,7 @@ var ClangUnknownCflags = sorted([]string{
 })
 
 var ClangLibToolingUnknownCflags = []string{
-	"-flto",
+	"-flto*",
 	"-fsanitize*",
 }