[JS IR] Support per-file mode and ES modules

js/js.translator/testData/box/esModules/crossModuleRefPerModule/topLevelMutableProperty.kt

@@ -0,0 +1,40 @@
+// DONT_TARGET_EXACT_BACKEND: JS
+// ES_MODULES
+// SPLIT_PER_MODULE
+// EXPECTED_REACHABLE_NODES: 1286
+// MODULE: lib
+// FILE: lib.kt
+package lib
+
+var foo = 23
+
+var bar: Int = 42
+    get() = field
+    set(value) {
+        field = value
+    }
+
+@JsName("faz") var baz = 99
+
+// MODULE: main(lib)
+// FILE: lib.kt
+package main
+
+import lib.*
+
+fun box(): String {
+    if (foo != 23) return "fail: simple property initial value: $foo"
+    foo = 24
+    if (foo != 24) return "fail: simple property new value: $foo"
+
+    if (bar != 42) return "fail: property with accessor initial value: $bar"
+    bar = 43
+    if (bar != 43) return "fail: property with accessor new value: $bar"
+
+    if (baz != 99) return "fail: renamed property initial value: $baz"
+    baz = 100
+    if (baz != 100) return "fail: renamed property new value: $baz"
+
+
+    return "OK"
+}