Update google_benchmark

Rolling v8/third_party/google_benchmark/src: https://chromium.googlesource.com/external/github.com/google/benchmark/+log/108ca84..920fa14

fix some build warnings on type conversions (Dominic Hamon)
https://chromium.googlesource.com/external/github.com/google/benchmark/+/920fa14

R=v8-waterfall-sheriff@grotations.appspotmail.com,mtv-sf-v8-sheriff@grotations.appspotmail.com,mlippautz@chromium.org

Change-Id: Ib4b588f343dca80474e2c7b7e3ed3f59a826324e
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3695963
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Cr-Commit-Position: refs/heads/main@{#81018}

DEPS

@@ -235,7 +235,7 @@ deps = {
     'dep_type': 'cipd',
   },
   'third_party/google_benchmark/src': {
-    'url': Var('chromium_url') + '/external/github.com/google/benchmark.git' + '@' + '108ca84820dc932957b75e6b31faa6c3cf0aa37a',
+    'url': Var('chromium_url') + '/external/github.com/google/benchmark.git' + '@' + '920fa14898d055d61b399160981271a45f49832a',
   },
   'third_party/googletest/src':
     Var('chromium_url') + '/external/github.com/google/googletest.git' + '@' + 'af29db7ec28d6df1c7f0f745186884091e602e07',