[llvm-strip] Add -o option to llvm-strip

This diff implements the option -o 
for specifying a file to write the output to.

Test plan: make check-all

Differential revision: https://reviews.llvm.org/D47505


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@333693 91177308-0d34-0410-b5e6-96231b3b80d8
3 files changed