Roll external/re2/ 611baecbc..0c5616df9 (14 commits)

https://github.com/google/re2/compare/611baecbcedc...0c5616df9c0a

$ git log 611baecbc..0c5616df9 --date=short --no-merges --format='%ad %ae %s'
2022-03-30 junyer Replace `StdIntMap` with `std::vector<int>`.
2022-03-24 junyer Use `std::unordered_map<int, int>` for `StdIntMap`.
2022-03-22 junyer Remove `xkcd.png`, which is disused.
2022-03-18 junyer Prog::Fanout() is no longer experimental.
2022-03-15 junyer Fall back to std::shared_mutex, not std::mutex.
2022-03-15 junyer Set CMAKE_CXX_STANDARD if we seem to need to set it. :/
2022-03-15 junyer Don't specify CMAKE_CXX_STANDARD anymore either.
2022-03-11 slyich Don't overwrite testinstall.cc in testinstall.
2022-03-03 junyer Add Clang 14 to the build matrix.
2022-02-24 junyer Simplify OS selection in Bazel by using @platforms.
2022-02-17 junyer Check __cpp_lib_string_view, not __cplusplus.
2022-01-27 junyer Oops, I think I needed pull_request_target instead.
2022-01-27 junyer Close all GitHub pull requests automatically.
2022-01-27 junyer Handle older macOS SDKs not defining TARGET_OS_OSX.

Created with:
  roll-dep external/re2
diff --git a/DEPS b/DEPS
index dd64427..2cfb341 100644
--- a/DEPS
+++ b/DEPS
@@ -5,7 +5,7 @@
 
   'effcee_revision': 'ddf5e2bb92957dc8a12c5392f8495333d6844133',
   'googletest_revision': '25dcdc7e8bfac8967f20fb2c0a628f5cf442188d',
-  're2_revision': '611baecbcedc9cec1f46e38616b6d8880b676c03',
+  're2_revision': '0c5616df9c0aaa44c9440d87422012423d91c7d1',
   'spirv_headers_revision': '6a55fade62dec6a406a5a721148f88a2211cbefa',
 }