[K/Wasm] Introduce stepping tests for Wasm

compiler/testData/debug/stepping/variablesWithoutInitializer.kt

@@ -1,3 +1,4 @@
+// IGNORE_BACKEND: WASM
 // FILE: test.kt
 
 fun box() {
@@ -17,18 +18,18 @@ fun box() {
 // The JVM backend does generate these line numbers as well.
 
 // EXPECTATIONS JVM JVM_IR
-// test.kt:4 box
 // test.kt:5 box
 // test.kt:6 box
 // test.kt:7 box
 // test.kt:8 box
 // test.kt:9 box
 // test.kt:10 box
-// test.kt:12 box
+// test.kt:11 box
+// test.kt:13 box
 
 // EXPECTATIONS JS_IR
-// test.kt:7 box
 // test.kt:8 box
 // test.kt:9 box
 // test.kt:10 box
-// test.kt:12 box
+// test.kt:11 box
+// test.kt:13 box