Hide log timestamps in test to prevent false failures

Author: robcasloz

test/hotspot/jtreg/compiler/intrinsics/bmi/BMITestRunner.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2014, 2020, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2014, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -122,6 +122,10 @@ public static OutputAnalyzer runTest(Class<? extends Expr> expr,
         List<String> vmOpts = new LinkedList<String>();
 
         Collections.addAll(vmOpts, additionalVMOpts);
+        // Hide timestamps from warnings (e.g. due to potential CDS
+        // saved/runtime state mismatch), to avoid false positives when
+        // comparing output across runs.
+        vmOpts.add("-Xlog:all=warning:stdout:level,tags");
 
         //setup mode-specific options
         switch (testVMMode) {