Tests: remove stepping tests on old JVM backend

compiler/testData/debug/stepping/class.kt

@@ -15,17 +15,11 @@ fun box() {
     a.foo()
 }
 
-// TODO: The JVM_IR backend has an extra line number on the return. This causes line
-// three to be hit both on entry to the constructor and on exit after storing the
-// value of prop.
-
-// EXPECTATIONS JVM JVM_IR
+// EXPECTATIONS JVM_IR
 // test.kt:13 box
 // test.kt:4 <init>
 // test.kt:5 <init>
-// EXPECTATIONS JVM_IR
 // test.kt:4 <init>
-// EXPECTATIONS JVM JVM_IR
 // test.kt:13 box
 // test.kt:14 box
 // test.kt:5 getProp
@@ -41,4 +35,4 @@ fun box() {
 // test.kt:4 <init>
 // test.kt:15 box
 // test.kt:9 foo
-// test.kt:16 box
+// test.kt:16 box