[foozzie] Migrate more harness adjustments to V8 repo

This adds printing on failures to compare output when correctness fuzzing.

TBR=yangguo@chromium.org
NOTRY=true

Bug: chromium:813833
Change-Id: I0280561392f6614960608db4e93341552c716142
Reviewed-on: https://chromium-review.googlesource.com/934843
Commit-Queue: Michael Achenbach <machenbach@chromium.org>
Reviewed-by: Michael Achenbach <machenbach@chromium.org>
Cr-Commit-Position: refs/heads/master@{#51529}

tools/clusterfuzz/v8_foozzie_harness_adjust.js

@@ -44,5 +44,18 @@ try {
       // Fall through to original version for all other types.
       return origPrettyPrinted(value);
     }
+
+    // We're not interested in stack traces.
+    this.MjsUnitAssertionError = function MjsUnitAssertionError(message) {}
+    MjsUnitAssertionError.prototype.toString = function () { return ""; };
+
+    // Do more printing in assertions for more correctness coverage.
+    this.failWithMessage = function failWithMessage(message) {
+      print(prettyPrinted(message))
+    }
+
+    this.fail = function fail(expectedText, found, name_opt) {
+      print(prettyPrinted(found));
+    }
   })();
 } catch(e) { }