Add the ability for the test suite to specify a list of compilers and a list of architectures

on the command line.  For example, use '-A x86_64^i386' to launch the inferior use both x86_64
and i386.

This is an example of building the debuggee using both clang and gcc compiers:

[17:30:46] johnny:/Volumes/data/lldb/svn/trunk/test $ ./dotest.py -C clang^gcc -v -f SourceManagerTestCase.test_modify_source_file_while_debugging

Session logs for test failures/errors will go into directory '2011-03-03-17_31_39'
Command invoked: python ./dotest.py -C clang^gcc -v -f SourceManagerTestCase.test_modify_source_file_while_debugging

Configuration:  compiler=clang
----------------------------------------------------------------------
Collected 1 test

1: test_modify_source_file_while_debugging (TestSourceManager.SourceManagerTestCase)
   Modify a source file while debugging the executable. ... Command 'run' failed!

original content: #include <stdio.h>

int main(int argc, char const *argv[]) {
    printf("Hello world.\n"); // Set break point at this line.
    return 0;
}

new content: #include <stdio.h>

int main(int argc, char const *argv[]) {
    printf("Hello lldb.\n"); // Set break point at this line.
    return 0;
}

os.path.getmtime() after writing new content: 1299202305.0
content restored to: #include <stdio.h>

int main(int argc, char const *argv[]) {
    printf("Hello world.\n"); // Set break point at this line.
    return 0;
}

os.path.getmtime() after restore: 1299202307.0
ok

----------------------------------------------------------------------
Ran 1 test in 8.259s

OK

Configuration:  compiler=gcc
----------------------------------------------------------------------
Collected 1 test

1: test_modify_source_file_while_debugging (TestSourceManager.SourceManagerTestCase)
   Modify a source file while debugging the executable. ... original content: #include <stdio.h>

int main(int argc, char const *argv[]) {
    printf("Hello world.\n"); // Set break point at this line.
    return 0;
}

new content: #include <stdio.h>

int main(int argc, char const *argv[]) {
    printf("Hello lldb.\n"); // Set break point at this line.
    return 0;
}

os.path.getmtime() after writing new content: 1299202307.0
content restored to: #include <stdio.h>

int main(int argc, char const *argv[]) {
    printf("Hello world.\n"); // Set break point at this line.
    return 0;
}

os.path.getmtime() after restore: 1299202309.0
ok

----------------------------------------------------------------------
Ran 1 test in 2.301s

OK
[17:31:49] johnny:/Volumes/data/lldb/svn/trunk/test $ 

llvm-svn: 126979