Benchmark the turnaround time starting a debugger and run to the breakpoint with lldb vs. gdb.

An example (with /Developer/usr/bin/lldb vs. /usr/bin/gdb):

[13:05:04] johnny:/Volumes/data/lldb/svn/trunk/test $ ./dotest.py -v +b -n -p TestCompileRunToBreakpointTurnaround.py
1: test_run_lldb_then_gdb (TestCompileRunToBreakpointTurnaround.CompileRunToBreakpointBench)
   Benchmark turnaround time with lldb vs. gdb. ... 
lldb turnaround benchmark: Avg: 4.574600 (Laps: 3, Total Elapsed Time: 13.723799)
gdb turnaround benchmark: Avg: 7.966713 (Laps: 3, Total Elapsed Time: 23.900139)
lldb_avg/gdb_avg: 0.574214
ok

----------------------------------------------------------------------
Ran 1 test in 55.462s

OK

llvm-svn: 142949