[llvm-objdump tests] Copy the inputs of tests closer to tests.

Summary:
Tests under tools/llvm-objdump should not use inputs from Object. Copied the
required inputs and aligned the new tests to be more consistent with the existing
tests in this respect.

Reviewers: ioeric

Reviewed By: ioeric

Subscribers: davide, djasper, cfe-commits

Differential Revision: https://reviews.llvm.org/D28799

llvm-svn: 292222