patman: Add a 'test' subcommand

At present we use --test to indicate that tests should be run. It is
better to use a subcommand for list, like binman. Change it and adjust
the existing code to fit under a 'send' subcommand, the default.

Give this subcommand the same default arguments as the others.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/tools/patman/test_util.py b/tools/patman/test_util.py
index 0827488..a87d3cc 100644
--- a/tools/patman/test_util.py
+++ b/tools/patman/test_util.py
@@ -47,7 +47,7 @@
         glob_list = []
     glob_list += exclude_list
     glob_list += ['*libfdt.py', '*site-packages*', '*dist-packages*']
-    test_cmd = 'test' if 'binman' in prog else '-t'
+    test_cmd = 'test' if 'binman' in prog or 'patman' in prog else '-t'
     prefix = ''
     if build_dir:
         prefix = 'PYTHONPATH=$PYTHONPATH:%s/sandbox_spl/tools ' % build_dir