Save Jack default extra args in a file

Change-Id: I059b36fc71679eb5c95f05ede26d8037c742921b
diff --git a/core/jack-default.args b/core/jack-default.args
new file mode 100644
index 0000000..8d70a82
--- /dev/null
+++ b/core/jack-default.args
@@ -0,0 +1,5 @@
+-D sched.runner=multi-threaded
+-D sched.runner.thread.kind=fixed
+-D sched.runner.thread.fixed.count=4
+--sanity-checks off
+-D jack.reporter.level.file=error=--,warning=-
\ No newline at end of file