[RuntimeDyld] Allow processRelocationRef to process more than one relocation entry at a time.

Some targets require more than one relocation entry to perform a relocation.
This change allows processRelocationRef to process more than one relocation
entry at a time by passing the relocation iterator itself instead of just
the relocation entry.

Related to <rdar://problem/16199095>

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@204439 91177308-0d34-0410-b5e6-96231b3b80d8