[ORC] Represent ORC interface names as SymbolNameSpecs (#224188)
Declare the bootstrap and controller-interface name constants (the SPSCI
descriptors, dispatch and alloc-action names, ProxySpec::Name) as
SymbolNameSpecs, pairing each name with its mangling kind at the point
of declaration. recordAddr and recordProxy now take a SymbolNameSpec and
mangle-and-intern it internally; executor-side registrations and the
remaining intern sites mangle the name too, so both sides still agree on
the symbol.
All names are Verbatim, so this is name-neutral (mangling is a no-op);
flipping any of them to a mangled kind (e.g. C) is a follow-up.