i#1282 part 1: fix crash by restoring arena var prior to cleanup
i#1282 part 1: fix crash by restoring arena var prior to cleanup

SVN-Revision: 1508

code4bones/drmemory,LohithBlaze/drmemory,code4bones/drmemory,sigma-random/drmemory,code4bones/drmemory,code4bones/drmemory,LohithBlaze/drmemory,sigma-random/drmemory,sigma-random/drmemory,LohithBlaze/drmemory,LohithBlaze/drmemory,code4bones/drmemory,LohithBlaze/drmemory,sigma-random/drmemory,sigma-random/drmemory