Reland "Reland "Implement PlatformThreadMetrics::GetCumulativeCPUUsage.""

This reverts commit f691d4465a95fc293b70ce0da069f7963e1b33da.

Reason for revert: Fixed ARM64 implementation, which doesn't support high-frequency timer. GetCPUUsageProportion was incorrectly treating
0 CPU as "uninitialized", but with low-frequency timers the first CPU
measurement can be rounded down to 0.

Original change's description:
> Revert "Reland "Implement PlatformThreadMetrics::GetCumulativeCPUUsage.""
>
> This reverts commit 1298f74e3b45c48bb3bcec37dd47d6e1b9dab115.
>
> Reason for revert: The test introduced by this CL is broken on win11-arm64-rel-tests (sample https://ci.chromium.org/ui/p/chromium/builders/ci/win11-arm64-rel-tests/4599/test-results)
>
> Bug: 420681350, 421933372
> Bug: 420681350
> Original change's description:
> > Reland "Implement PlatformThreadMetrics::GetCumulativeCPUUsage."
> >
> > This reverts commit b5b67dac989ddaf27ce978ee9bbedd1b591eed45.
> >
> > Reason for revert: Fixed failing test.
> >
> > When GetCumulativeCPUUsage_OtherThread sleeps for a period, it's
> > possible that the thread doing busy work never gets scheduled. Instead
> > put the timer in the thread doing the busy work, and have the test sleep
> > until it's signalled from the other thread.
> >
> > Bug: 420681350 Original change's description:
> > > Revert "Implement PlatformThreadMetrics::GetCumulativeCPUUsage."
> > >
> > > This reverts commit 9a6d8c106b0c54c19774ce6aa9fe6a8fae503c89.
> > >
> > > Reason for revert: crbug.com/421933372
> > >
> > > Bug: 420681350, 421933372
> > > Original change's description:
> > > > Implement PlatformThreadMetrics::GetCumulativeCPUUsage.
> > > >
> > > > Bug: 420681350
> > > > Change-Id: Ic30ddd42ec1b6ec5d1325d6fe804159d59c16447
> > > > Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6553924
> > > > Auto-Submit: Joe Mason <joenotcharles@google.com>
> > > > Reviewed-by: Francois Pierre Doray <fdoray@chromium.org>
> > > > Commit-Queue: Joe Mason <joenotcharles@google.com>
> > > > Commit-Queue: Francois Pierre Doray <fdoray@chromium.org>
> > > > Cr-Commit-Position: refs/heads/main@{#1468349}
> > >
> > > Bug: 420681350
> > > Change-Id: I7ec556c55c249f1dcfc1f6832cbc74adb212af1b
> > > Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6615099
> > > Bot-Commit: Rubber Stamper <rubber-stamper@appspot.gserviceaccount.com>
> > > Owners-Override: Anders Hartvoll Ruud <andruud@google.com>
> > > Commit-Queue: Anders Hartvoll Ruud <andruud@chromium.org>
> > > Cr-Commit-Position: refs/heads/main@{#1468617}
> >
> > Bug: 420681350, 421933372
> > Bug: 420681350
> > Change-Id: I5a42bf6af2310bc0fdfca33a903d3c23b0be5661
> > Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6618448
> > Commit-Queue: Francois Pierre Doray <fdoray@chromium.org>
> > Auto-Submit: Joe Mason <joenotcharles@google.com>
> > Reviewed-by: Francois Pierre Doray <fdoray@chromium.org>
> > Cr-Commit-Position: refs/heads/main@{#1469231}
>
> Bug: 420681350 Original change's description:
> Bug: 420681350, 421933372
> Bug: 420681350
> No-Presubmit: true
> No-Tree-Checks: true
> No-Try: true
> Change-Id: Ie0d6d896b3b8c671a52b8e464cac76d07b7af7a5
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6616553
> Reviewed-by: Samuel Huang <huangs@chromium.org>
> Auto-Submit: Andrey Kosyakov <caseq@chromium.org>
> Reviewed-by: Francois Pierre Doray <fdoray@chromium.org>
> Commit-Queue: Francois Pierre Doray <fdoray@chromium.org>
> Bot-Commit: Rubber Stamper <rubber-stamper@appspot.gserviceaccount.com>
> Cr-Commit-Position: refs/heads/main@{#1469573}

Bug: 420681350, 421933372
Bug: 420681350
Bug: 420681350 Original change's description:
Change-Id: I15fc80f4ad9e2ee3861f6b91584d50595223b383
Cq-Include-Trybots: luci.chromium.try:win-arm64-rel
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6622197
Reviewed-by: Francois Pierre Doray <fdoray@chromium.org>
Commit-Queue: Joe Mason <joenotcharles@google.com>
Reviewed-by: Andrey Kosyakov <caseq@chromium.org>
Auto-Submit: Joe Mason <joenotcharles@google.com>
Commit-Queue: Francois Pierre Doray <fdoray@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1469778}