[compiler] Add simple walltime measurement (#32331)

Adds a new Timing logger event to the compiler which currently only
records the walltime of running the compiler from the time the babel
plugin's Program visitor enters to the time it exits.

To enable, run the compiler with `ENABLE_REACT_COMPILER_TIMINGS=1 ...`
or `export ENABLE_REACT_COMPILER_TIMINGS=1` to set it by default.