Avoid unnecessary FindClass("java/lang/String").

Use previously retrieved global reference instead.
Check for NULL after creating the global reference.

Change-Id: I21670d2ef0f63ddb5801dd21e7e56359e5519479
Correct Date format for el_GR, sv_SE and tr_TR locales

Amend DateFormat.getDateFormat to CLDR data from icu4c
instead of locale specific resource entries which are incorrect
for several locales.

No CTS tests are added as they require changing the locale which
is not currently possible.

Bug: https://code.google.com/p/android/issues/detail?id=56385

Change-Id: Ibd11c7fd9b595e19a3e2bf508e1585aa50067e03
Signed-off-by: howardb <android@howardb.com>
Merge "Correct Date format for el_GR, sv_SE and tr_TR locales"
Merge "Avoid unnecessary FindClass("java/lang/String")."