Many profiling related tests make assumptions on the profiling settings,
e.g. opt_prof is off by default, and prof_active is default on when opt_prof is
on. However the default settings can be changed via --with-malloc-conf at build
time. Fixing the tests by adding the assumed settings explicitly.
Existing backtrace implementations skip native stack frames from runtimes like
Python. The hook allows to augment the backtraces to attribute allocations to
native functions in heap profiles.