Ignore trace entries generated by dev tools

[antross]

Currently some calls various browsers dev tools make end up in the trace, but having the tools open is useful to pair with features like device emulation. Need to see if there's some way to determine that the caller is tooling to filter such calls from the log.

[antross]

Some experimentation with new Error().stack suggests this might be possible.

Calls can potentially be ignored if only tracer code is in the stack or if the bottom of the stack is not page code (e.g. marked (native code) in Edge or <anonymous> in Chrome - unclear if Firefox has an equivalent). Care would have to be taken to avoid accidentally ignoring callback contexts and to make sure no non-tooling cases match these patterns.