[IR] add testdata for dumpKotlinLike

compiler/testData/ir/irText/expressions/whenUnusedExpression.kt.txt

@@ -0,0 +1,15 @@
+fun test(b: Boolean, i: Int) {
+  when {
+    b -> { //BLOCK
+      { //BLOCK
+        val tmp0_subject: Int = i
+        when {
+          EQEQ(arg0 = tmp0_subject, arg1 = 0) -> 1 /*~> Unit */
+          true -> null /*~> Unit */
+        }
+      }
+    }
+    true -> null /*~> Unit */
+  }
+}
+