[dsymutil] Automatically generate a reproducer when dsymutil crashes

[dsymutil] Automatically generate a reproducer when dsymutil crashes

Automatically generate a reproducer when dsymutil crashes. We already
support generating reproducers with the --gen-reproducer flag, which
emits a reproducer on exit. This patch adds support for doing the same
on a crash and makes it the default behavior.

rdar://68357665

Differential revision: https://reviews.llvm.org/D127441