Revert^2 "Enable -Wsingle-bit-bitfield-constant-conversion"

This reverts commit e64573b0c0433438dcb7bf7060dfd793e470e05f.

Reason for revert: re-submit after fixing build breaks.

Change-Id: Ia43b8ffa23355f14e656ce086b23e1ca0d3821ca
diff --git a/cc/config/global.go b/cc/config/global.go
index 0e8fff6..c838357 100644
--- a/cc/config/global.go
+++ b/cc/config/global.go
@@ -287,8 +287,7 @@
 		"-Wno-error=deprecated-builtins", // http://b/241601211
 		"-Wno-error=deprecated",          // in external/googletest/googletest
 		// New warnings to be fixed after clang-r475365
-		"-Wno-error=single-bit-bitfield-constant-conversion", // http://b/243965903
-		"-Wno-error=enum-constexpr-conversion",               // http://b/243964282
+		"-Wno-error=enum-constexpr-conversion", // http://b/243964282
 		// New warnings to be fixed after clang-r522817
 		"-Wno-error=invalid-offsetof",
 		"-Wno-error=thread-safety-reference-return",