Use re2_fuzzer stored in re2 repository, remove old version.

testing/libfuzzer/fuzzers/BUILD.gn

 # Copyright 2015 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 # Individual libfuzzer tests that didn't find their home yet.
 
 import("//build/config/features.gni")
 import("//media/media_options.gni")
 import("//testing/libfuzzer/fuzzer_test.gni")
 
@@ skipping 315 matching lines @@
 }
 
 fuzzer_test("v8_wasm_types_section_fuzzer") {
   sources = []
   deps = [
     "//v8:wasm_types_section_fuzzer",
   ]
   libfuzzer_options = [ "max_len=500" ]
 }
 
-fuzzer_test("third_party_re2_fuzzer") {
-  sources = [
-    "re2_fuzzer.cc",
-  ]
-  deps = [
-    "//third_party/re2:re2",
-  ]
-}
-
 fuzzer_test("libxml_xml_regexp_compile_fuzzer") {
   sources = [
     "libxml_xml_regexp_compile_fuzzer.cc",
   ]
   deps = [
     "//third_party/libxml",
   ]
   libfuzzer_options = [ "max_len=32" ]
   additional_configs = [ "//testing/libfuzzer:no_clusterfuzz" ]
 }
@@ skipping 83 matching lines @@
 }
 
 fuzzer_test("hash_fuzzer") {
   sources = [
     "hash_fuzzer.cc",
   ]
   deps = [
     "//base",
   ]
 }