Java 8 RFR 8014319: Faster division of large integers

[Brian Burkhalter]

Math Reviewers:

This review request encompasses the incorporation of the Burnikel-Ziegler recursive division algorithm into BigInteger. As presented, it applies when the large integers involved are each represented by at least 50 ints. This algorithm crossover threshold is subject to change pending further experimentation.

This patch is identical to the original contribution from Tim Buktu

http://mail.openjdk.java.net/pipermail/core-libs-dev/2013-July/018784.html

aside from some minor cosmetic javadoc updates in MutableBigInteger and the addition of the divideLarge() method and some other minor changes in BigIntegerTest.

Issue:	http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=8014319
Webrev:	http://cr.openjdk.java.net/~bpb/8014319/

Thanks,

Brian

[1] http://cr.yp.to/bib/1998/burnikel.ps
[2] http://bioinfo.ict.ac.cn/%7Edbu/AlgorithmCourses/Lectures/Hasselstrom2003.pdf