[Orc] Properly deallocate mapped memory in MapperJITLinkMemoryManager

When memory is deallocated from MapperJITLinkMemoryManager deinitialize
actions are run through mapper and in case of InProcessMapper, memory
protections of the region are reset to read/write as they were previously
changed and can be reused in future.

Differential Revision: https://reviews.llvm.org/D131768