RFR(T) 8216199: Local variable arg defined but never used in BCEscapeAnalyzer::compute_escape_for_intrinsic()

[zgu at redhat.com]

Please review this trivial change to remove unused local variable.

Bug: https://bugs.openjdk.java.net/browse/JDK-8216199
Webrev: http://cr.openjdk.java.net/~zgu/JDK-8216199/webrev.00/

Test:

  hotspot_compiler on Linux 64 (fastdebug and release)

Thanks,

-Zhengyu