[CP] Cherry-Pick "[cfe] Ensure default values in synthesized function nodes" into stable #55714
Description
Commit(s) to merge
Target
stable
Prepared changelist for beta/stable
https://dart-review.googlesource.com/c/sdk/+/366300
Issue Description
Without this fix some apps run into crashes of the dart2wasm compiler, see #55529
What is the fix
The fix is to ensure synthetic functions created by CFE have default values for parameters where needed.
Why cherry-pick
We don't want customers to run into dart2wasm crashes in next stable branch.
Risk
If we run all CI tests on cherry-pick requests then risk is low.
Issue link(s)
Extra Info
No response