Fix bug: FunctionDeclaration may have missing name (#20618)

tests/cases/fourslash/extract-method-in-anonymous-function-declaration.ts

@@ -0,0 +1,20 @@
+/// <reference path='fourslash.ts' />
+
+////export default function() {
+////    /*start*/0/*end*/
+////}
+
+goTo.select('start', 'end')
+edit.applyRefactor({
+    refactorName: "Extract Symbol",
+    actionName: "function_scope_0",
+    actionDescription: "Extract to inner function in anonymous function",
+    newContent:
+`export default function() {
+    /*RENAME*/newFunction();
+
+    function newFunction() {
+        0;
+    }
+}`
+});