[CanonicalizeOSSALifetime] Ignore debug_values.

Added Kind::DebugValueInst to the list of opcodes that
CanonicalizeOSSALifetime doesn't go out of its way to hoist over.

Author: nate-chandler

include/swift/SILOptimizer/Utils/CanonicalOSSALifetime.h

@@ -285,6 +285,7 @@ class CanonicalizeOSSALifetime {
   /// be hoisted over to avoid churn and infinite looping.
   static bool ignoredByDestroyHoisting(SILInstructionKind kind) {
     switch (kind) {
+    case SILInstructionKind::DebugValueInst:
     case SILInstructionKind::DestroyValueInst:
     case SILInstructionKind::CopyValueInst:
     case SILInstructionKind::BeginBorrowInst: