toggle --prof and --prof_lazy

[Raynos]

Can we toggle these flags at run time ?

They are not in the current documentation.

cc @rf

[thlorenz]

Gonna have a look at this - haven't had time to try them all.

[thlorenz]

@Raynos they are in the documentation though: https://github.com/thlorenz/v8-flags/blob/master/flags-0.10.md#prof-false-boolean

[thlorenz]

BTW looks promising since FLAG_prof doesn't seem to be part of the bootstrapping process, but is queried repeatedly so turning it on/off later should have the desired effect.