Fix DUPn_Xm handling in PopBackwardPropagationTransformer

DUPn_Xm instructions implicitly depend on elements directly under stack
top (which are not "copied", but still required). We can't analyze them
precisely now, and should skip methods containing these instructions.
Fortunately, we didn't generate these instructions under POP before,
but with new range check code generation and constant conditions
elimination such combination of instructions becomes possible.

compiler/backend/src/org/jetbrains/kotlin/codegen/optimization/boxing/PopBackwardPropagationTransformer.kt

@@ -33,9 +33,17 @@ import java.util.*
 class PopBackwardPropagationTransformer : MethodTransformer() {
     override fun transform(internalClassName: String, methodNode: MethodNode) {
         if (!OptimizationMethodVisitor.canBeOptimizedUsingSourceInterpreter(methodNode)) return
+        if (methodNode.instructions.toArray().any { it.isUnsafeStackInsn() }) return
         Transformer(methodNode).transform()
     }
 
+    // TODO better stack operations analysis
+    private fun AbstractInsnNode.isUnsafeStackInsn() =
+            opcode == Opcodes.DUP_X1 ||
+            opcode == Opcodes.DUP_X2 ||
+            opcode == Opcodes.DUP2_X1 ||
+            opcode == Opcodes.DUP2_X2
+
     private class Transformer(val methodNode: MethodNode) {
         private interface Transformation {
             fun apply(insn: AbstractInsnNode)