To support compile time localization, we need to be
able to provide the locales via a well known global property.
This commit changes `getLocaleData()` so that it will attempt
to read the local from the global `ng.common.locales` if the
locale has not already been registered via `registerLocaleData()`.
PR Close#33523
To limit the exposure of the private `LOCALE_DATA` from outside
`@angular/core` this commit exposes private functions in the core
to hide the internal structures better.
* The `registerLocaleData()` implementation has moved from
`@angular/common` to `@angular/core`. A stub that delegates to
core has been left in common for backward compatibility.
* A new `ɵunregisterLocaleData()` function has been provided,
which is particularly useful in tests to clear out registered locales
to prevent subsequent tests from being affected.
* A private export of `ɵregisterLocaleData()` has been removed
from `@angular/common`. This was not being used and is accessible
via `@angular/core` anyway.
PR Close#33523