[foozzie] Mock out Realm.eval

A new realm doesn't contain the mocks and suppressions on the global
object for correctness fuzzing. We replace Realm.eval with eval to
keep exercising the code.

Bug: chromium:1071133
Change-Id: Iffe82d37bf08829fc5937c17c2089277403e71dc
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2153206
Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Commit-Queue: Michael Achenbach <machenbach@chromium.org>
Cr-Commit-Position: refs/heads/master@{#67187}

test/mjsunit/tools/foozzie.js

@@ -77,3 +77,6 @@ if (isBigEndian){
 else {
   testArrayType(Float64Array, [0, 1072693248]);
 }
+
+// Realm.eval is just eval.
+assertEquals(1477662728716, Realm.eval(Realm.create(), `Date.now()`));

tools/clusterfuzz/v8_mock.js

@@ -159,3 +159,6 @@ Object.defineProperty(
     }
   };
 })();
+
+// Mock Realm.
+Realm.eval = function(realm, code) { return eval(code) };