feat(ext/web): add performance.clearResourceTimings() and setResourceTimingBufferSize() (#31603)
This PR implements the missing Performance API methods as specified in
the [W3C Performance Timeline
spec](https://www.w3.org/TR/performance-timeline/#dom-performance-clearresourcetimings):
- `clearResourceTimings()`: Removes all performance entries with an
`entryType` of "resource" from the performance timeline
- `setResourceTimingBufferSize(maxSize)`: Sets the desired size of the
browser's resource timing buffer
Closes #13605