[9] RFR (S) : JDK-8039915 NumberFormat.format() does not consider required no. of fraction digits properly

[olivier.lagneau at oracle.com]

Please review this fix in for wrong rounding-mode mode behavior of 
NumberFormat.format(double) in HALF_UP case.

https://bugs.openjdk.java.net/browse/JDK-8039915

webrev: http://cr.openjdk.java.net/~olagneau/8039915/webrev.00 
<http://cr.openjdk.java.net/%7Eolagneau/8039915/webrev.00>

Bug came from a mix of a '5' and 'greater than 5' last digit, when this 
digit was the last one.

Fix consists in properly separating the two cases and cleanly test all 
possible cases (see JDK-8039915 comments) for the HALF_UP rounding-mode.

TieRoundingTest test has been extended with a few cases to check such 
cases (last digit at the rounding position and != '5')

testing: jtreg, jck8, jprt

Best regards,
Olivier Lagneau