Skip higher-order funcs for inference triggers

[timholy]

When identifying the caller of an inference-triggering callee, sometimes it's nice to skip over higher order functions. For instance in a do-block, you might prefer to attribute any inference trigger in the anonymous function to the parent scope that implemented the do-block rather than the higher-order function used by the do-statement.

[timholy]

Test failure is due to a timing shift and unrelated to this PR. Will fix in a separate PR.