swift

f625cce6 - [concurrency] NFC refactor out some code from LowerHopToActor before changing the pass.

[concurrency] NFC refactor out some code from LowerHopToActor before changing the pass. Specifically, I am refactoring out the code that converts actor/Optional<any Actor> to an executor in preparation for adding code to LowerHopToExecutor that handles Builtin.ImplicitIsolationActor. The only actual functional change is that I made getExecutorForOptionalActor support being invoked when generating code (i.e. when its SILBuilder has an insertion point at the end of the block). It previously assumed that it would always have a real SILInstruction as an insertion point. The changes can be seen in the places where we now check if the insertion point equals the end of a block. Its very minor and due to conditional control flow doesn't have any actual impact given the manner that the code today is generated. This came up in a subsequent commit when I reuse this code to generate a helper function for converting Builtin.ImplicitIsolationActor to Builtin.Executor. (cherry picked from commit 21915ae4283b6494538bd3f822203eceabfb2e34) Conflicts: lib/SILOptimizer/Mandatory/LowerHopToActor.cpp