Revert "Reset main-custom to the latest main code"

This reverts commit b0e703ec66051a4905142ec2a91670241a9fc878.

Reason for revert: breaks v8-perf result parsing

Original change's description:
> Reset main-custom to the latest main code
>
> Change-Id: Ic89816520b7929e50c673b60a39a44c35fe85996
> Reviewed-on: https://chromium-review.googlesource.com/c/external/github.com/WebKit/JetStream/+/6905285
> Reviewed-by: Leszek Swirski <[email protected]>

No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Change-Id: I101c80628156fb9635a19e95159a62435ff35926
Reviewed-on: https://chromium-review.googlesource.com/c/external/github.com/WebKit/JetStream/+/6906865
Bot-Commit: Rubber Stamper <[email protected]>
162 files changed