[move-only] Rather than calling the borrow to destructure transform from the MoveOnlyObjectChecker, make its own pass.

This is a cleaner separation of concerns. The reason why I did not do this
originally is that I thought I would need to reuse this functionality in the
address checker, but this issue actually does not come up there since we project
the address and then load instead of load and then project.

Author: gottesmm

include/swift/SILOptimizer/PassManager/Passes.def

@@ -460,9 +460,12 @@ PASS(MovedAsyncVarDebugInfoPropagator, "sil-moved-async-var-dbginfo-propagator",
      "Propagate debug info from moved async vars after coroutine funclet boundaries")
 PASS(MoveOnlyDeinitInsertion, "sil-move-only-deinit-insertion",
      "After running move only checking, convert last destroy_values to deinit calls")
-PASS(MoveOnlyBorrowToDestructureTransform, "sil-move-only-borrow-to-destructure",
-     "Utility pass that is used to test the borrow to destructure transform "
-     "independently of the move only object/address checkers")
+PASS(MoveOnlyBorrowToDestructureTransform,
+     "sil-move-only-borrow-to-destructure",
+     "Pass that is phased ordered before move only object checking that is "
+     "used to convert borrow+projection to destructures. Once this has run, the move "
+     "only object checker runs and ensures that the destructures do not create "
+     "any move only errors with respect to non-borrow+projection uses")
 PASS(PruneVTables, "prune-vtables",
      "Mark class methods that do not require vtable dispatch")
 PASS_RANGE(AllPasses, AADumper, PruneVTables)

lib/SILOptimizer/Mandatory/CMakeLists.txt

@@ -29,7 +29,6 @@ target_sources(swiftSILOptimizer PRIVATE
   MoveOnlyDeinitInsertion.cpp
   MoveOnlyDiagnostics.cpp
   MoveOnlyObjectChecker.cpp
-  MoveOnlyUtils.cpp
   NestedSemanticFunctionCheck.cpp
   OptimizeHopToExecutor.cpp
   PerformanceDiagnostics.cpp