Tests: remove stepping tests on old JVM backend

compiler/testData/debug/stepping/iincStepping.kt

@@ -1,5 +1,5 @@
 // IGNORE_BACKEND: WASM
-// IGNORE_BACKEND: JVM
+
 // FILE: test.kt
 fun box() {
     var i = 0
@@ -18,16 +18,7 @@ fun box() {
             1
 }
 
-// The current backend has strange stepping behavior for assignments.
-// It generates the line number for the assignment first, and then
-// the evaluation of the right hand side with line numbers.
-// That leads to the line number with the assignment typically
-// not being hit at all as it has no instructions. Also, stepping
-// through the evaluation of the right hand side and then hitting
-// the line number for the actual assignment makes more sense as
-// that is the actual evaluation order.
-
-// EXPECTATIONS JVM JVM_IR
+// EXPECTATIONS JVM_IR
 // test.kt:5 box
 // test.kt:6 box
 // test.kt:7 box
@@ -57,4 +48,4 @@ fun box() {
 // test.kt:13 box
 // test.kt:15 box
 // test.kt:17 box
-// test.kt:19 box
+// test.kt:19 box