RFR(T) 8216200: BCEscapeAnalyzer::ArgumentMap::set_intersect() is incorrect

[zgu at redhat.com]

Please review this trivial change that removes unused/incorrect method.

BCEscapeAnalyzer::ArgumentMap::set_intersect()'s implementation is
wrong. The reason that it did not blowup anything, is that it does not
have users. 

We can fix it or remove it: based on Tobias' comment in bug, let's
simply remove it. 


Bug: https://bugs.openjdk.java.net/browse/JDK-8216200
Webrev: http://cr.openjdk.java.net/~zgu/JDK-8216200/webrev.00/

Test:

  hotspot_compiler on Linux 64.

Thanks,

-Zhengyu