Bitcode: Check file size before reading bitcode header.

Should unbreak ocaml binding tests.

Also added an llvm-dis test that checks for the same thing.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@285777 91177308-0d34-0410-b5e6-96231b3b80d8
3 files changed