RFR(S): 8241492: Strip mining not working for test/hotspot/jtreg/compiler/c2/Test6850611.java

[Roland Westrelin]

https://bugs.openjdk.java.net/browse/JDK-8241492
http://cr.openjdk.java.net/~roland/8241492/webrev.00/

The loop is strip mined but the computation of the inner loop number of
iterations is wrong. It is the min of the number of iterations left and
LoopStripMiningIter. In this case, the number of iterations left
(guaranteed always positive) is greater than the max signed int but the
min() that's used operates on signed ints so even though there's a large
number of iterations left, the resulting number of iterations is not
LoopStripMiningIter. Switching to a unsigned min() fixes this.

Roland.