Revert "Disable ubsan diagnostics under HWASan."

The original problem has been fixed in LLVM:
https://reviews.llvm.org/rG78f7e6d8d7956cb96d0fa0fd606192ca0218eee1

Bug: 191808836
Bug: 209991446
Test: m net_test_btm_iso with SANITIZE_TARGET=hwaddress

This reverts commit b15a564869.

Change-Id: Ie99a9a204e0a3f7c3ddf3efd74ac7f19db90215a

cc/sanitize.go

@@ -539,11 +539,6 @@ func (sanitize *sanitize) begin(ctx BaseModuleContext) {
 	if Bool(s.Hwaddress) {
 		s.Address = nil
 		s.Thread = nil
-		// Disable ubsan diagnosic as a workaround for a compiler bug.
-		// TODO(b/191808836): re-enable.
-		s.Diag.Undefined = nil
-		s.Diag.Integer_overflow = nil
-		s.Diag.Misc_undefined = nil
 	}
 
 	// TODO(b/131771163): CFI transiently depends on LTO, and thus Fuzzer is