binman: Run tests concurrently

At present the tests run one after the other using a single CPU. This is
not very efficient. Bring in the concurrencytest module and run the tests
concurrently, using one process for each CPU by default. A -P option
allows this to be overridden, which is necessary for code-coverage to
function correctly.

This requires fixing a few tests which are currently not fully
independent.

At some point we might consider doing this across all pytests in U-Boot.
There is a pytest version that supports specifying the number of processes
to use, but it did not work for me.

Signed-off-by: Simon Glass <sjg@chromium.org>

tools/binman/cmdline.py

@@ -46,6 +46,8 @@ def ParseArgs(argv):
     parser.add_option('-p', '--preserve', action='store_true',\
         help='Preserve temporary output directory even if option -O is not '
              'given')
+    parser.add_option('-P', '--processes', type=int,
+                      help='set number of processes to use for running tests')
     parser.add_option('-t', '--test', action='store_true',
                     default=False, help='run tests')
     parser.add_option('-T', '--test-coverage', action='store_true',