CLDR-18253 Add en-TW and fix japanese calendar tests for en

[AEApple]

CLDR-18253

• [ ] This PR completes the ticket.

ALLOW_MANY_COMMITS=true

[macchiati]

Just added an exception in tools/cldr-code/src/test/java/org/unicode/cldr/unittest/TestCoverageLevel.java. Let's see if that works. (The real fix should do some different checks, but if this works we can use for now.)

[macchiati]

I think you just need to squash, then I'll approve

[macchiati]

Ah, I just fixed japanese. Need roc also