[RuntimeDyld] Add alignment arguments to the reserveAllocationSpace method of

[RuntimeDyld] Add alignment arguments to the reserveAllocationSpace method of
RuntimeDyld::MemoryManager.

The RuntimeDyld::MemoryManager::reserveAllocationSpace method is called when
object files are loaded, and gives clients a chance to pre-allocate memory for
all segments. Previously only the size of each segment (code, ro-data, rw-data)
was supplied but not the alignment. This hasn't caused any problems so far, as
most clients allocate via the MemoryBlock interface which returns page-aligned
blocks. Adding alignment arguments enables finer grained allocation while still
satisfying alignment restrictions.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@257294 91177308-0d34-0410-b5e6-96231b3b80d8