Tests: remove stepping tests on old JVM backend

compiler/testData/debug/stepping/variablesWithoutInitializer.kt

@@ -12,12 +12,7 @@ fun box() {
     }
 }
 
-// The JVM IR backend does generate line number information for the
-// declaration of local variables without initializer.
-// Stepping through those is useful for breakpoinnts.
-// The JVM backend does generate these line numbers as well.
-
-// EXPECTATIONS JVM JVM_IR
+// EXPECTATIONS JVM_IR
 // test.kt:5 box
 // test.kt:6 box
 // test.kt:7 box
@@ -32,4 +27,4 @@ fun box() {
 // test.kt:9 box
 // test.kt:10 box
 // test.kt:11 box
-// test.kt:13 box
+// test.kt:13 box