CLDR breaks BTR build

[KaneFreeman]

Bug

BTR build for dojo/site fails during the Cldr init step.

Package Version: 7.0.0-alpha.9 (dojo/framework 7.0.0-alpha.10)

Code

https://github.com/KaneFreeman/site/tree/upgrade

Environment: Windows 10 / Node 12

Expected behavior:

Should build sucessfully

Actual behavior:

Throws the following warnings/errors during the build and then just hangs there.

/ building(node:13228) UnhandledPromiseRejectionWarning: TypeError: Cannot read property '0' of undefined
(node:13228) UnhandledPromiseRejectionWarning: Unhandled promise rejection. This error originated either by throwing inside of an async function without a catch block, or by rejecting a promise which was not handled with .catch(). (rejection id: 2)
(node:13228) [DEP0018] DeprecationWarning: Unhandled promise rejections are deprecated. In the future, promise rejections that are not handled will terminate the Node.js process with a non-zero exit code.
\ building(node:13228) UnhandledPromiseRejectionWarning: TypeError: Cannot read property '0' of undefined
(node:13228) UnhandledPromiseRejectionWarning: Unhandled promise rejection. This error originated either by throwing inside of an async function without a catch block, or by rejecting a promise which was not handled with .catch(). (rejection id: 3)
| building(node:13228) UnhandledPromiseRejectionWarning: TypeError: Cannot read property '0' of undefined
(node:13228) UnhandledPromiseRejectionWarning: Unhandled promise rejection. This error originated either by throwing inside of an async function without a catch block, or by rejecting a promise which was not handled with .catch(). (rejection id: 4)
\ building(node:13228) UnhandledPromiseRejectionWarning: TypeError: Cannot read property '0' of undefined
(node:13228) UnhandledPromiseRejectionWarning: Unhandled promise rejection. This error originated either by throwing inside of an async function without a catch block, or by rejecting a promise which was not handled with .catch(). (rejection id: 5)
/ building(node:13228) UnhandledPromiseRejectionWarning: TypeError: Cannot read property '0' of undefined
(node:13228) UnhandledPromiseRejectionWarning: Unhandled promise rejection. This error originated either by throwing inside of an async function without a catch block, or by rejecting a promise which was not handled with .catch(). (rejection id: 6)
Error: Uncaught [TypeError: Cannot read property '0' of undefined]
    at reportException (s:\Repositories\GitHub\dojo\site\node_modules\jsdom\lib\jsdom\living\helpers\runtime-script-errors.js:62:24)
    at Timeout.callback [as _onTimeout] (s:\Repositories\GitHub\dojo\site\node_modules\jsdom\lib\jsdom\browser\Window.js:645:7)
    at listOnTimeout (internal/timers.js:531:17)
    at processTimers (internal/timers.js:475:7) TypeError: Cannot read property '0' of undefined
    at coreRemoveLikelySubtags (http://localhost:62786/main.js:4364:28)
    at http://localhost:62786/main.js:4479:17
    at Array.forEach (<anonymous>)
    at arrayForEach (http://localhost:62786/main.js:4451:17)
    at bundleLookup (http://localhost:62786/main.js:4475:4)
    at Cldr.init (http://localhost:62786/main.js:4799:12)
    at Cldr.init (http://localhost:62786/main.js:5423:13)
    at Cldr.init (http://localhost:62786/main.js:5554:13)
    at new Cldr (http://localhost:62786/main.js:4724:8)
    at alwaysCldr (http://localhost:62786/main.js:6097:55)```