Now that the skwasm and canvaskit renderers emit the same frame events (see #175392), the expectedBenchmarkMetrics method here [1] no longer returns the expected events. They are now be the same for both skwasm and canvaskit.

To handle this, I suggest making useWasm an optional named parameter instead of required.

[1] https://github.com/flutter/packages/blob/1c0be204c45eea42927eb6005bb45f16a8fffb07/packages/web_benchmarks/lib/src/metrics.dart#L152-L155

(Note: This was noticed because the DevTools benchmark tests to began failing, see flutter/devtools#9456)