Fix JS source maps for delegates and backing fields

js/js.translator/testData/lineNumbers/backingField.kt

@@ -0,0 +1,15 @@
+open class A {
+    open var x = 23
+
+    var y: String = "42"
+        get() = field +
+                "!"
+        set(value) {
+            print(
+                    field)
+            field =
+                    value.removeSuffix("!")
+        }
+}
+
+// LINES: 2 4 2 2 * 5 6 8 9 10 11

js/js.translator/testData/lineNumbers/delegatedProperty.kt

@@ -0,0 +1,18 @@
+import kotlin.reflect.*
+
+open class A {
+    var x: String by
+            B()
+}
+
+class B {
+    operator fun getValue(thisRef: Any?, property: KProperty<*>): String {
+        return "OK"
+    }
+
+    operator fun setValue(thisRef: Any?, property: KProperty<*>, value: String) {
+        println(value)
+    }
+}
+
+// LINES: 4 5 4 4 2 * 10 * 14

js/js.translator/testData/lineNumbers/delegation.kt

@@ -0,0 +1,21 @@
+class A :
+    I
+    by o
+
+interface I {
+    fun foo(): String
+
+    var bar: Int
+}
+
+val o = object : I {
+    override fun foo(): String = "foo"
+
+    override var bar: Int
+        get() = 23
+        set(value) {
+            println(value)
+        }
+}
+
+// LINES: 2 3 2 2 * 2 * 12 * 15 17