JS: make JS parser to store function's name in AST. See KT-15475

js/js.parser/src/com/google/gwt/dev/js/JsAstMapper.java

@@ -570,7 +570,7 @@ public class JsAstMapper {
         //
         String fnNameIdent = fromFnNameNode.getString();
         if (fnNameIdent != null && fnNameIdent.length() > 0) {
-            scopeContext.globalNameFor(fnNameIdent);
+            toFn.setName(scopeContext.globalNameFor(fnNameIdent));
         }
 
         while (fromParamNode != null) {

js/js.tests/test/org/jetbrains/kotlin/js/test/semantics/BoxJsTestGenerated.java

@@ -4967,6 +4967,12 @@ public class BoxJsTestGenerated extends AbstractBoxJsTest {
             doTest(fileName);
         }
 
+        @TestMetadata("functionName.kt")
+        public void testFunctionName() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("js/js.translator/testData/box/jsCode/functionName.kt");
+            doTest(fileName);
+        }
+
         @TestMetadata("if.kt")
         public void testIf() throws Exception {
             String fileName = KotlinTestUtils.navigationMetadata("js/js.translator/testData/box/jsCode/if.kt");

js/js.translator/testData/box/jsCode/functionName.kt

@@ -0,0 +1,8 @@
+fun box(): String {
+    return js("""
+        function foo() {
+            return "OK";
+        }
+        foo();
+    """)
+}