Revert r369190, r369192 ([llvm-readobj/llvm-readelf] - Improve/cleanup the error reporting API.)

It caused multiple BB failtures:

http://lab.llvm.org:8011/builders/clang-x64-windows-msvc/builds/9743/steps/stage%201%20check/logs/stdio
http://lab.llvm.org:8011/builders/clang-cmake-x86_64-sde-avx512-linux/builds/26042/steps/ninja%20check%201/logs/FAIL%3A%20LLVM%3A%3Astack-sizes.test

llvm-svn: 369193