RFR(S): 8134468: Lucene test failures with 32 bit JDK 9b78, Server compiler

[Roland Westrelin]

http://cr.openjdk.java.net/~roland/8134468/webrev.00/

The computations in ArrayCopyNode::modifies() can overflow on 32bits and the return value can then be incorrect (an array load can then bypass an arraycopy that modifies that array element). Actually I’m not sure why I used intptr_t in the initial change. I probably wanted a 64 bit integer and used the wrong type.

Roland.