Use APIs for creating terminator results that handle forwarding
ownership consistently.
Add ManagedValue::forForwardedRValue(SILValue) to handle cleanups
consistently based on ownership forwarding.
Add SILGenBuilder::createForwardedTermResult(SILType type) for
creating termator results with the correct ownership and cleanups.
Add SILGenBuilder::createTermResult(SILType type, ValueOwnershipKind
ownership) that handles cleanup based on terminator result ownership.
Add SILGenBuilder::createOptionalSomeResult(SwitchEnumInst) so a lot
of code doesn't need to deal with unwrapping Optional types,
terminator results, and ownership rules.
Replace the existing "phi" APIs with a single
SILGenBuilder::createPhi(SILType, ValueOwnershipKind) that handles
cleanup based on phi ownership.
Phis and terminator results are fundamentally different and need to be handled differently everywhere. Remove the confusion where terminator results were generated with a "phi argument" API.
* [Distributed] cleanup some warnings in SILGenDistributed
* [Distributed] cleanup SILGenDestructor, move dist logic to
SILGenDistributed
* [Distributed] de-duplicate SIL gen for if remote/local branch
