test(KT-31614): fixate behavior of serialization/deserialization of UTF characters.

js/js.translator/testData/incremental/invalidation/unicodeSerializationAndDeserialization/main/m.kt

@@ -0,0 +1,24 @@
+
+fun box(step: Int): String {
+    return when (step) {
+        0 -> checkStep(step, qux = "\uD800", quz = "\uD800")
+        1 -> checkStep(step, qux = "\uDB6A", quz = "\uD800")
+        2 -> checkStep(step, qux = "\uDB6A", quz = "\uDFFF")
+        else -> "Unknown Step"
+    }
+}
+
+fun checkStep(step: Int, qux: String, quz: String): String {
+    val a = qux()
+    val b = quz()
+
+    if (a != qux || a == "?") {
+        return "Fail(qux): Step $step"
+    }
+
+    if (b != quz || b == "?") {
+        return "Fail(quz): Step $step"
+    }
+
+    return "OK"
+}

js/js.translator/testData/incremental/invalidation/unicodeSerializationAndDeserialization/main/module.info

@@ -0,0 +1,7 @@
+STEP 0:
+    dependencies: stdlib, lib1, lib2, lib3
+    dirty: m.kt
+STEP 1:
+    dependencies: stdlib, lib1, lib2, lib3
+STEP 2:
+    dependencies: stdlib, lib1, lib2, lib3