Add a helper for "git bisect run ..."

Author: BanzaiMan

tool/git_bisect_run.sh

@@ -0,0 +1,13 @@
+#! /bin/sh
+
+# simple script for use with 'git bisect run'
+# e.g., git bisect run tool/git_bisect_run.sh -T--1.9 spec/ruby/language/defined_spec.rb
+# arguments will be passed on to mspec.
+
+cd `dirname $0`/..
+if [ ! -e spec/mspec ]; then
+  ant fetch-stable-specs
+fi
+
+ant clean jar
+jruby spec/mspec/bin/mspec $*