[K/Wasm] Introduce stepping tests for Wasm

compiler/testData/debug/stepping/psvm.kt

@@ -1,3 +1,4 @@
+// IGNORE_BACKEND: WASM
 // FILE: test.kt
 
 fun main(args: Array<String>) {
@@ -9,13 +10,13 @@ fun box() {
 }
 
 // EXPECTATIONS JVM JVM_IR
-// test.kt:8 box
-// test.kt:4 main
-// test.kt:5 main
 // test.kt:9 box
+// test.kt:5 main
+// test.kt:6 main
+// test.kt:10 box
 
 // EXPECTATIONS JS_IR
-// test.kt:8 box
-// test.kt:4 main
+// test.kt:9 box
 // test.kt:5 main
-// test.kt:9 box
+// test.kt:6 main
+// test.kt:10 box