[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/valParameter.kt

@@ -7,4 +7,4 @@ fun foo() {
     A(23, "foo")
 }
 
-// LINES: 1 2 3 * 8 7 7
+// LINES: 1 2 3 * 6 8 7 7