[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/elvis.kt

@@ -9,4 +9,4 @@ fun box(x: String?) {
 
 fun foo() = "bar"
 
-// LINES: 8 7 7 4 4 4 5 5 7 7 7 7 * 5 4 5 10 10 10 * 1 * 1
+// LINES: 3 8 7 7 4 4 4 5 5 7 7 7 7 * 5 4 5 10 10 10 * 1 * 1