[Backport] 8333396: Use StringBuilder internally for java.text.Format.* formatting

[lingjun-cg]

[Backport] 8333396: Use StringBuilder internally for java.text.Format.* formatting

Summary: java.text.Format. use StringBuffer internally, but StringBuffer's bad performance character become obvious after obsoleting biased locking. So use StringBuilder if possible in java.text.Formating..

Testing: All java.text.format jtreg.

Reviewers: D-D-H, Yude Lin

Issue: https://github.com/dragonwell-project/dragonwell21/issues/83

[linade]

Is this a clean backport?

[linade]

Also does it change any public api that might break any existing dw21 applications

[linade]

lgtm, effectively clean backport without touching public api, only some description changes

[lingjun-cg]

Also does it change any public api that might break any existing dw21 applications

No public api changed.

[lingjun-cg]

Is this a clean backport?

Yes. There are only some minor conflicts at the topmost of file that contains "Copyright ".