Do not add duplicate $completion when compiling JVM against JVM_IR

This change fixes JvmOldAgainstIrBoxInlineTestGenerated.Suspend and
JvmIrAgainstOldBoxInlineTestGenerated.Suspend tests.

compiler/backend/src/org/jetbrains/kotlin/codegen/coroutines/CoroutineTransformerMethodVisitor.kt

@@ -230,6 +230,16 @@ class CoroutineTransformerMethodVisitor(
             if (last is LabelNode) last as LabelNode
             else LabelNode().also { insert(last, it) }
         }
+
+        // When compiling with the old backend against the bytecode generated by JVM IR, $completion may already be in LVT.
+        if (methodNode.localVariables.any {
+                it.name == SUSPEND_FUNCTION_COMPLETION_PARAMETER_NAME &&
+                        areLabelsBeforeSameInsn(startLabel, it.start) &&
+                        areLabelsBeforeSameInsn(endLabel, it.end)
+            }) {
+            return
+        }
+
         methodNode.localVariables.add(
             LocalVariableNode(
                 SUSPEND_FUNCTION_COMPLETION_PARAMETER_NAME,

compiler/backend/src/org/jetbrains/kotlin/codegen/inline/inlineCodegenUtils.kt

@@ -317,6 +317,9 @@ internal fun firstLabelInChain(node: LabelNode): LabelNode {
     return curNode
 }
 
+internal fun areLabelsBeforeSameInsn(first: LabelNode, second: LabelNode): Boolean =
+    firstLabelInChain(first) == firstLabelInChain(second)
+
 internal val MethodNode?.nodeText: String
     get() {
         if (this == null) {