Date locale functions fail if Map is overridden

[lpd-au]

https://stackoverflow.com/a/44637643/646551

Steps to reproduce

Run the following code using ch.exe:

// var earlyDateString = new Date().toLocaleString();
Map = {};
var dateString = new Date().toLocaleString();

Expected result

dateString contains something like "‎20‎/‎06‎/‎2017‎ ‎5‎:‎46‎:‎36‎ ‎PM"

Actual result

TypeError: Intl is not available.
   at Global code (e:\my downloads\cc_windows_1_5_2\bin\x64_release\test.js:3:1)

Workaround

Uncomment the first line so Intl is initialised before Map is overridden.

Other browsers

Google Chrome: Not affected
Mozilla Firefox: Not affected

[curtisman]

Probably regression from #2358

[dilijev]

Yep, looks like tainting affected the maps being used in the caches which caused Intl to fail to initialize. The fix is probably to expose a platform.Map and use new platform.Map() instead of new Map().

[dilijev]

I have a fix. Will post the PR momentarily.