Elaborate a little bit on the documentation for running tests locally (#402). r=bhearsum
Elaborate a little bit on the documentation for running tests locally (#402). r=bhearsum


testbhearsum/balrog,testbhearsum/balrog,testbhearsum/balrog,mozbhearsum/balrog,testbhearsum/balrog,mozbhearsum/balrog,mozbhearsum/balrog,mozbhearsum/balrog