The 'generate_resmoke_suite.py' file will divide all the tests in a suite into sub-suite based on their runtime and a target max runtime. There may be cases where we want to limit the number of sub-suites it should create. This work is to add an optional command line argument that allows the caller to specify the max number of sub-suites and implement logic to limit the number of sub-suites when that option is specified.

Note: If the limit is hit, it is acceptable to random assign the remaining tests into sub-suites (i.e. we don't need to optimally pack the extra suites based on runtime).