systemc: Add a --working-dir option to the test config.py.

The tests expect to be run from a certain directory. Generally that
doesn't matter, but in at least one case the test opens a file with a
relative path, and that doesn't work unless CWD is what it expects.

Change-Id: I34c0ed975e77daed50ace4f7eebd034bf04c5595
Reviewed-on: https://gem5-review.googlesource.com/12271
Reviewed-by: Gabe Black <gabeblack@google.com>
Maintainer: Gabe Black <gabeblack@google.com>

src/systemc/tests/config.py

@@ -27,7 +27,9 @@
 
 from __future__ import print_function
 
+import argparse
 import m5
+import os
 import re
 
 from m5.objects import SystemC_Kernel, Root
@@ -37,6 +39,13 @@ from m5.objects import SystemC_Kernel, Root
 kernel = SystemC_Kernel()
 root = Root(full_system=True, systemc_kernel=kernel)
 
+parser = argparse.ArgumentParser()
+parser.add_argument('--working-dir')
+
+args = parser.parse_args()
+if args.working_dir:
+    os.chdir(args.working_dir)
+
 kernel.sc_main("Hello", "World");
 
 m5.instantiate(None)