[lld-macho] Enable EH frame relocation / pruning

This just removes the code that gates the logic. The main issue here is
perf impact: without {D122258}, LLD takes a significant perf hit because
it now has to do a lot more work in the input parsing phase. But with
that change to eliminate unnecessary EH frames from input object files,
the perf overhead here is minimal. Concretely, here are the numbers for
some builds as measured on my 16-core Mac Pro:

**chromium_framework**

This is without the use of `-femit-dwarf-unwind=no-compact-unwind`:

             base           diff           difference (95% CI)
  sys_time   1.826 ± 0.019  1.962 ± 0.034  [  +6.5% ..   +8.4%]
  user_time  9.306 ± 0.054  9.926 ± 0.082  [  +6.2% ..   +7.1%]
  wall_time  8.225 ± 0.068  8.947 ± 0.128  [  +8.0% ..   +9.6%]
  samples    15             22

With that flag enabled, the regression mostly disappears, as hoped:

             base           diff           difference (95% CI)
  sys_time   1.839 ± 0.062  1.866 ± 0.068  [...