Add an option '-S' to skip the build and cleanup while running the test.

Use this option with care as you would need to build the inferior(s) by hand
and build the executable(s) with the correct name(s).  This option can be used
with '-# n' to stress test certain test cases for n number of times.

An example:

[11:55:11] johnny:/Volumes/data/lldb/svn/trunk/test/python_api/value $ ls
Makefile		TestValueAPI.pyc	linked_list
TestValueAPI.py		change_values		main.c
[11:55:14] johnny:/Volumes/data/lldb/svn/trunk/test/python_api/value $ make EXE=test_with_dsym
clang -gdwarf-2 -O0  -arch x86_64   -c -o main.o main.c
clang -gdwarf-2 -O0  -arch x86_64   main.o -o "test_with_dsym"
/usr/bin/dsymutil  -o "test_with_dsym.dSYM" "test_with_dsym"
[11:55:20] johnny:/Volumes/data/lldb/svn/trunk/test/python_api/value $ cd ../..
[11:55:24] johnny:/Volumes/data/lldb/svn/trunk/test $ ./dotest.py -v -# 10 -S -f ValueAPITestCase.test_with_dsym
LLDB build dir: /Volumes/data/lldb/svn/trunk/build/Debug
LLDB-89
Path: /Volumes/data/lldb/svn/trunk
URL: https://johnny@llvm.org/svn/llvm-project/lldb/trunk
Repository Root: https://johnny@llvm.org/svn/llvm-project
Repository UUID: 91177308-0d34-0410-b5e6-96231b3b80d8
Revision: 144914
Node Kind: directory
Schedule: normal
Last Changed Author: gclayton
Last Changed Rev: 144911
Last Changed Date: 2011-11-17 09:22:31 -0800 (Thu, 17 Nov 2011)



Session logs for test failures/errors/unexpected successes will go into directory '2011-11-17-11_55_29'
Command invoked: python ./dotest.py -v -# 10 -S -f ValueAPITestCase.test_with_dsym
----------------------------------------------------------------------
Collected 1 test

1: test_with_dsym (TestValueAPI.ValueAPITestCase)
   Exercise some SBValue APIs. ... ok

----------------------------------------------------------------------
Ran 1 test in 1.163s

OK
1: test_with_dsym (TestValueAPI.ValueAPITestCase)
   Exercise some SBValue APIs. ... ok

----------------------------------------------------------------------
Ran 1 test in 0.200s

OK
1: test_with_dsym (TestValueAPI.ValueAPITestCase)
   Exercise some SBValue APIs. ... ok

----------------------------------------------------------------------
Ran 1 test in 0.198s

OK
1: test_with_dsym (TestValueAPI.ValueAPITestCase)
   Exercise some SBValue APIs. ... ok

----------------------------------------------------------------------
Ran 1 test in 0.199s

OK
1: test_with_dsym (TestValueAPI.ValueAPITestCase)
   Exercise some SBValue APIs. ... ok

----------------------------------------------------------------------
Ran 1 test in 0.239s

OK
1: test_with_dsym (TestValueAPI.ValueAPITestCase)
   Exercise some SBValue APIs. ... ok

----------------------------------------------------------------------
Ran 1 test in 1.215s

OK
1: test_with_dsym (TestValueAPI.ValueAPITestCase)
   Exercise some SBValue APIs. ... ok

----------------------------------------------------------------------
Ran 1 test in 0.105s

OK
1: test_with_dsym (TestValueAPI.ValueAPITestCase)
   Exercise some SBValue APIs. ... ok

----------------------------------------------------------------------
Ran 1 test in 0.098s

OK
1: test_with_dsym (TestValueAPI.ValueAPITestCase)
   Exercise some SBValue APIs. ... ok

----------------------------------------------------------------------
Ran 1 test in 0.195s

OK
1: test_with_dsym (TestValueAPI.ValueAPITestCase)
   Exercise some SBValue APIs. ... ok

----------------------------------------------------------------------
Ran 1 test in 1.197s

OK
[11:55:34] johnny:/Volumes/data/lldb/svn/trunk/test $ 

llvm-svn: 144919