[llvm-readobj] Downgrade 'PT_DYNAMIC segment offset + size exceeds the size of the file' from an error to a warning
Summary: This allows llvm-readobj to print other useful information for truncated files instead of giving up.
Reviewers: jhenderson, grimar, MaskRay
Reviewed By: jhenderson, grimar, MaskRay
Differential Revision: https://reviews.llvm.org/D66036