[ORC] Mangle memory-access CI names as C rather than Verbatim (#225066)
Flip the memory-access wrapper descriptors (MemoryAccessSPSCI.h) from
Verbatim to C., so their names carry the target's C mangling (a leading
'_' on Darwin, no-op elsewhere). First step of moving the ORC runtime
controller-interface names to C to match an upcoming runtime change. The
controller (recordProxy) and the in-tree executor (OrcRTBootstrap,
mangledCopy) mangle these same specs, so they stay in sync; nothing else
defines these names.