[JS BE] Make sourceMap generation more precise

- Don't produce mapping for closing bracket in case of expressionBody
 - Map Kt*Function declaration into corresponding js fun declaration
 - Update test data & add new test

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

@@ -15,4 +15,4 @@ class B {
     }
 }
 
-// LINES: 3 4 5 * 4 4 4 * 8 11 10 10 15 14 14
+// LINES: 3 4 5 * 4 4 4 * 8 9 11 10 10 13 15 14 14