[foozzie] Add Big*64Array to mock file

To prevent correctness fuzzers from finding spurious differences
between architectures, we need to mock out the maximum length of
all TypedArrays. This patch adds the two new types BigInt64Array
and BigUint64Array to the existing list.

Bug: chromium:894864
Change-Id: I5cdeeafa597b09aee2d9b4d368c07f10008baf58
Reviewed-on: https://chromium-review.googlesource.com/c/1285399
Commit-Queue: Michael Achenbach <machenbach@chromium.org>
Reviewed-by: Michael Achenbach <machenbach@chromium.org>
Cr-Commit-Position: refs/heads/master@{#56710}

tools/clusterfuzz/v8_mock_archs.js

@@ -40,6 +40,8 @@
   Uint16Array = mock(Uint16Array);
   Int32Array = mock(Int32Array);
   Uint32Array = mock(Uint32Array);
+  BigInt64Array = mock(BigInt64Array);
+  BigUint64Array = mock(BigUint64Array);
   Float32Array = mock(Float32Array);
   Float64Array = mock(Float64Array);
 })();
@@ -54,6 +56,8 @@
     Uint16Array,
     Int32Array,
     Uint32Array,
+    BigInt64Array,
+    BigUint64Array,
     Float32Array,
     Float64Array,
   ];