JS: add explanation to inline/arrayLiteralAliasing.kt test

js/js.translator/testData/inline/cases/arrayLiteralAliasing.kt

@@ -1,3 +1,29 @@
+/*
+This tests that variables (aliases) are created for array literals.
+
+Let's say we have the following JS code:
+
+function f(a) {
+    a.push(0);
+    return a;
+}
+
+// ...
+console.log(f([]));
+In this case copying f's argument a without creating a variable is incorrect because it would produce the following code:
+
+[].push(0);
+console.log([]);
+This is the correct version:
+
+var a = [];
+a.push(0);
+console.log(a);
+The test was created because we don't want to create aliases for literals.
+However in our class hierarchy JsArrayLiteral is subclass of JsLiteral,
+which makes very easy to implement incorrect aliasing logic.
+ */
+
 package foo
 
 // CHECK_NOT_CALLED: moveTo