[lldb/Test] Add `use_colors` argument to PExpect.launch wrapper

[mib]

Summary

This patch adds a new use_colors argument to the PExpect.launch
method.

As the name suggests, it allows the user to conditionally enable color
support in the debugger, which can be helpful to test functionalities that
rely on that, like progress reporting. It defaults to False.

Signed-off-by: Med Ismail Bennani <[e-mail]>

[JDevlieghere]

LGTM

lldb/packages/Python/lldbsuite/test/lldbpexpect.py

class PExpectTest(TestBase):
 
     NO_DEBUG_INFO_TESTCASE = True
     PROMPT = "(lldb) "
 
     def expect_prompt(self):
         self.child.expect_exact(self.PROMPT)
 
     def launch(self, executable=None, extra_args=None, timeout=60,
-               dimensions=None, run_under=None, post_spawn=None):
+               dimensions=None, run_under=None, post_spawn=None,
+               use_colors=False):
         logfile = getattr(sys.stdout, 'buffer',
                             sys.stdout) if self.TraceOn() else None
 
         args = []
         if run_under is not None:
             args += run_under
-        args += [lldbtest_config.lldbExec, '--no-lldbinit', '--no-use-colors']
+        args += [lldbtest_config.lldbExec, '--no-lldbinit']
+        if not use_colors:
+            args += '--no-use-colors'
         for cmd in self.setUpCommands():
+            if use_colors and "use-color false" not in cmd:
                 args += ['-O', cmd]
         if executable is not None:
             args += ['--file', executable]
         if extra_args is not None:
             args.extend(extra_args)
 
         env = dict(os.environ)
         env["TERM"] = "vt100"
         env["HOME"] = self.getBuildDir()
 
         import pexpect
         self.child = pexpect.spawn(
                 args[0], args=args[1:], logfile=logfile,
                 timeout=timeout, dimensions=dimensions, env=env)
         self.child.ptyproc.delayafterclose = timeout/10
         self.child.ptyproc.delayafterterminate = timeout/10
 
         if post_spawn is not None:
             post_spawn()
         self.expect_prompt()
         for cmd in self.setUpCommands():
+            if use_colors and "use-color false" not in cmd:
                 self.child.expect_exact(cmd)
                 self.expect_prompt()
         if executable is not None:
             self.child.expect_exact("target create")
             self.child.expect_exact("Current executable set to")
             self.expect_prompt()
 
     def expect(self, cmd, substrs=None):
         self.assertNotIn('\n', cmd)
         # If 'substrs' is a string then this code would just check that every