Apply suggestions from code review

Co-authored-by: Sid Vishnoi <8426945+sidvishnoi@users.noreply.github.com>

Author: marcoscaceres

tests/static/xref/disambiguation.test.js

@@ -46,7 +46,7 @@ const overload = (uri) => ({
 });
 
 describe("xref/script - detectOverloadedEntries", () => {
-  it("does not throw (no Map.prototype.getOrInsert) and flags overloaded pairs", () => {
+  it("flags overloaded pairs", () => {
     const pairs = detectOverloadedEntries(
       [overload(URI_A), overload(URI_B)],
       "postMessage()",
@@ -74,9 +74,7 @@ describe("xref/script - detectOverloadedEntries", () => {
     expect(pairs.size).toBe(0);
   });
 
-  it("handles entries with no `for` list (the former getOrInsert path)", () => {
-    // These entries hit the else branch that previously called the unshipped
-    // Map.prototype.getOrInsert; the empty forContext key is "".
+  it("handles entries with no `for` list", () => {
     const noFor = (uri) => ({
       type: "method",
       spec: "html",