FileCheck tool crashes when trying to parse --check-prefix argument if there is no any
data after it.
For example test like following would crash if there are no symbols and no EOL mark after `boom`:
# REQUIRES: x86
# RUN: <skipped few lines>
# RUN: llvm-readobj -t %t | FileCheck %s --check-prefix=boom
Patch fixes the issue.
Differential revision: https://reviews.llvm.org/D42057
llvm-svn: 322536