[v8] Turn on the new libfuzzer fuzzer for multi-returns

R=inferno@chromium.org

Change-Id: Ida49d839c1a0ccfd60d4ba556f6225000c81f3a6
Reviewed-on: https://chromium-review.googlesource.com/895533Reviewed-by: Abhishek Arya <inferno@chromium.org>
Commit-Queue: Abhishek Arya <inferno@chromium.org>
Cr-Commit-Position: refs/heads/master@{#533284}

testing/libfuzzer/fuzzers/BUILD.gn

@@ -227,6 +227,13 @@ fuzzer_test("v8_regexp_builtins_fuzzer") {
   ]
 }
 
+fuzzer_test("v8_multi_return_fuzzer") {
+  sources = []
+  deps = [
+    "//v8:multi_return_fuzzer",
+  ]
+}
+
 fuzzer_test("v8_wasm_code_fuzzer") {
   sources = []
   deps = [