[loc-en-dev] Locale.toString() with language and script/extension without country/variant

[Yoshito Umaoka]

While testing private use tags, I discovered one more issue in 
Locale.toString().

Our design goal was to put script and extensions after variant. By doing 
so, they look like a part of variant from old Java releases. However, it 
does not work well when a Locale has language and script/extensions, but 
no country or variants.

For example:

Locale.forLanguageTag("en-Latn").toString() -> Expected: "en__#Latn" / 
Actual: "en_#Latn"
Locale.forLanguageTag("en-x-123").toString() -> Expected: "en__#x-123" / 
Actual: "en_#x-123"

The current behavior may confuse old Java programs assuming the second 
field separated by "_" is country. I think we should also fix this 
problem before JDK 7 final release.

-Yoshito