llvm/test/Object/archive-big-extract.test

## Test extract xcoff object file from AIX big archive.
# RUN: rm -rf %t && mkdir -p %t/extracted/ && cd %t/extracted/
# RUN: llvm-ar x %p/Inputs/aix-big-archive.a
# RUN: echo "content_of_evenlen" > evenlen_1
# RUN: cmp evenlen evenlen_1