Don't error in the ELFFile constructor.

All error checking now happens when the information is needed. The
only thing left is the minimum size of the buffer and that can be just
a precondition. I will add an ErrorOr create method in a followup
commit.

Also don't store a pointer to the Header, since it is just a trivial
cast.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@285961 91177308-0d34-0410-b5e6-96231b3b80d8
2 files changed