Manual changes:
1. Fix generate_test_spec_json.py to correctly handle ADDITIONAL_MIXINS
   Needed after angle_skia_gold_test mixin removed from Chromium in
   crrev.com/890333
2. Copy third_party/logdog from Chromium
   Needed after crrev.com/890539 in order to create isolates on Android
   and for tools/perf/process_perf_results.py

Change log: https://chromium.googlesource.com/chromium/src/+log/6c5859c895..399855f4bb
Full diff: https://chromium.googlesource.com/chromium/src/+/6c5859c895..399855f4bb

Changed dependencies
* build: https://chromium.googlesource.com/chromium/src/build.git/+log/8870cb4120..2192a63c23
* buildtools: https://chromium.googlesource.com/chromium/src/buildtools.git/+log/c793cca886..9d8449e380
* buildtools/linux64: git_revision:39a87c0b36310bdf06b692c098f199a0d97fc810..git_revision:393dab000d704a4364d085fa4c01ec7af176c8fa
* buildtools/mac: git_revision:39a87c0b36310bdf06b692c098f199a0d97fc810..git_revision:393dab000d704a4364d085fa4c01ec7af176c8fa
* buildtools/third_party/libc++abi/trunk: https://chromium.googlesource.com/external/github.com/llvm/llvm-project/libcxxabi.git/+log/7e3b76855b..2c53623d59
* buildtools/win: git_revision:39a87c0b36310bdf06b692c098f199a0d97fc810..git_revision:393dab000d704a4364d085fa4c01ec7af176c8fa
* testing: https://chromium.googlesource.com/chromium/src/testing/+log/a62f8260df..ab567bcc84
* third_party/abseil-cpp: https://chromium.googlesource.com/chromium/src/third_party/abseil-cpp/+log/7949d87093..bd17c406ba
* third_party/android_deps: https://chromium.googlesource.com/chromium/src/third_party/android_deps/+log/887e8d9009..fa47598982
* third_party/android_sdk: https://chromium.googlesource.com/chromium/src/third_party/android_sdk/+log/1cfc90728e..816daa2545
* third_party/catapult: https://chromium.googlesource.com/catapult.git/+log/{catapult_..17cf72ca75
* third_party/depot_tools: https://chromium.googlesource.com/chromium/tools/depot_tools.git/+log/b508ecd932..6d099d543d
* third_party/nasm: https://chromium.googlesource.com/chromium/deps/nasm.git/+log/19f3fad68d..e9be5fd6d7
* third_party/protobuf: https://chromium.googlesource.com/chromium/src/third_party/protobuf/+log/82f8803671..f4241bd0f2
* third_party/turbine: _iPtB_ThhxlMOt2TsYqVppwriEEn0mp-NUNRwDwYLUAC..Om6yIEXgJxuqghErK29h9RcMH6VaymMbxwScwXmcN6EC
* tools/clang: https://chromium.googlesource.com/chromium/src/tools/clang.git/+log/09481f56be..fd14318cc9
* tools/luci-go: git_revision:2cc9805d5ad186367461ef1c4f0c59098b450418..git_revision:725192cc79f07ea946e10a64baac06625c206968
* tools/luci-go: git_revision:2cc9805d5ad186367461ef1c4f0c59098b450418..git_revision:725192cc79f07ea946e10a64baac06625c206968
* tools/luci-go: git_revision:2cc9805d5ad186367461ef1c4f0c59098b450418..git_revision:725192cc79f07ea946e10a64baac06625c206968
* tools/mb: https://chromium.googlesource.com/chromium/src/tools/mb/+log/94630dfc19..12c8fa872b
* tools/perf: https://chromium.googlesource.com/chromium/src/tools/perf/+log/5c84710692..2e6477d751
DEPS diff: https://chromium.googlesource.com/chromium/src/+/6c5859c895..399855f4bb/DEPS

Clang version changed llvmorg-13-init-11999-g50c0aaed:llvmorg-13-init-12491-g055770d5
Details: https://chromium.googlesource.com/chromium/src/tools/clang/+/09481f56be7b1bbaf5a466be5d81691902825fcf..fd14318cc948b67e5ec8a0f2f7563142ccd6dac2/scripts/update.py

Bug: angleproject:4483, angleproject:6037
Change-Id: I9035126bce55642d4dfce54eeace85093bdd1782
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2954241Reviewed-by: Jamie Madill <jmadill@chromium.org>
Commit-Queue: Yuly Novikov <ynovikov@chromium.org>