Add an option '-s session-dir-name' to overwrite the default timestamp-named

directory used to dump the session info for test failures/errors.

Example:

/Volumes/data/lldb/svn/trunk/test $ ./dotest.py -s jason -v array_types

Session info for test errors or failures will go into directory jason
----------------------------------------------------------------------
Collected 4 tests

test_with_dsym_and_python_api (TestArrayTypes.ArrayTypesTestCase)
Use Python APIs to inspect variables with array types. ... ok
test_with_dsym_and_run_command (TestArrayTypes.ArrayTypesTestCase)
Test 'frame variable var_name' on some variables with array types. ... ok
test_with_dwarf_and_python_api (TestArrayTypes.ArrayTypesTestCase)
Use Python APIs to inspect variables with array types. ... ok
test_with_dwarf_and_run_command (TestArrayTypes.ArrayTypesTestCase)
Test 'frame variable var_name' on some variables with array types. ... FAIL

======================================================================
FAIL: test_with_dwarf_and_run_command (TestArrayTypes.ArrayTypesTestCase)
Test 'frame variable var_name' on some variables with array types.
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/Volumes/data/lldb/svn/trunk/test/array_types/TestArrayTypes.py", line 27, in test_with_dwarf_and_run_command
    self.array_types()
  File "/Volumes/data/lldb/svn/trunk/test/array_types/TestArrayTypes.py", line 62, in array_types
    'stop reason = breakpoint'])
  File "/Volumes/data/lldb/svn/trunk/test/lldbtest.py", line 594, in expect
    self.runCmd(str, trace = (True if trace else False), check = not error)
  File "/Volumes/data/lldb/svn/trunk/test/lldbtest.py", line 564, in runCmd
    msg if msg else CMD_MSG(cmd, True))
AssertionError: False is not True : Command 'thread list' returns successfully

----------------------------------------------------------------------
Ran 4 tests in 3.086s

FAILED (failures=1)
/Volumes/data/lldb/svn/trunk/test $ ls jason
TestArrayTypes.ArrayTypesTestCase.test_with_dwarf_and_run_command.log
/Volumes/data/lldb/svn/trunk/test $ head -10 jason/TestArrayTypes.ArrayTypesTestCase.test_with_dwarf_and_run_command.log 
Session info generated @ Thu Oct 21 09:54:15 2010

os command: [['/bin/sh', '-c', 'make clean; make MAKE_DSYM=NO']]
stdout: rm -rf "a.out" "a.out.dSYM"  main.o main.d
cc -arch x86_64 -gdwarf-2 -O0   -c -o main.o main.c
cc -arch x86_64 -gdwarf-2 -O0  main.o -o "a.out"

stderr: None
retcode: 0

/Volumes/data/lldb/svn/trunk/test $ 

llvm-svn: 117028