Feature: tools: add crm_simulate option to repeat profiling tests

crm_simulate's --profile option will now use clock() to determine and print the
CPU time used by each test in the profile directory.

A new --repeat <N> option causes each test to be repeated <N> times, for better
timing comparisons.

Example:
crm_simulate --profile cts/scheduler --repeat 1000

• Testing cts/scheduler/year-2038.xml ... 32.21 secs
• Testing cts/scheduler/whitebox-unexpectedly-running.xml ... 0.89 secs
• Testing cts/scheduler/whitebox-stop.xml ... 3.08 secs
• Testing cts/scheduler/whitebox-start.xml ... 3.16 secs

(etc.)