@formatjs/intl-datetimeformat: missing am/pm indicator in some locales

[hasyimibhar]

Which package?
@formatjs/intl-datetimeformat

Describe the bug
When hour12 is set to true and hourCycle is set to h12, the output of format is missing the am/pm indicator for some locales. From my test (not exhaustive), it's missing for the following locales:

• en-MY
• id-ID
• zh-Hant-HK (下午 instead of pm is missing)
• ja-JP (午後 instead of pm is missing)

To Reproduce
Steps to reproduce the behavior:

Run this with Node.js:
https://gist.github.com/hasyimibhar/bc8e17ce4f922253ede90b1070f3c1a1

It outputs 01 Feb 2020, 06:10:10.

Replace en-MY to test with other locales.

Expected behavior
On Chrome Version 86.0.4240.111 (Official Build) (x86_64), it outputs 01 Feb 2020, 06:10:10 pm.

Screenshots
If applicable, add screenshots to help explain your problem.

Desktop (please complete the following information):

• OS: [e.g. iOS]
• Browser [e.g. chrome, safari]
• Version [e.g. 22]

Smartphone (please complete the following information):

• Device: [e.g. iPhone6]
• OS: [e.g. iOS8.1]
• Browser [e.g. stock browser, safari]
• Version [e.g. 22]

Additional context
Add any other context about the problem here.

[longlho]

Thanks for reporting! We'll take a look asap.