Eliminate the TestStarted-XXX and TestFinished-XXX files from check-lldb runs.

Nobody seems to know what purpose these files serve, yet they were accumulating by the thousands in the test traces directory.  I'm proposing we delete them.

Creating these files accounted for about 2.5% of the time to run ninja check-lldb on my machine, which isn't a lot, but it's something.

llvm-svn: 263122

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

@@ -987,12 +987,6 @@ def run_suite():
         except OSError as exception:
             if exception.errno != errno.EEXIST:
                 raise
-    where_to_save_session = os.getcwd()
-    fname = os.path.join(configuration.sdir_name, "TestStarted-%d" % os.getpid())
-    with open(fname, "w") as f:
-        print("Test started at: %s\n" % timestamp_started, file=f)
-        print(configuration.svn_info, file=f)
-        print("Command invoked: %s\n" % getMyCommandLine(), file=f)
 
     #
     # Invoke the default TextTestRunner to run the test suite, possibly iterating
@@ -1109,11 +1103,6 @@ def run_suite():
         for category in configuration.failuresPerCategory:
             sys.stderr.write("%s - %d\n" % (category, configuration.failuresPerCategory[category]))
 
-    os.chdir(where_to_save_session)
-    fname = os.path.join(configuration.sdir_name, "TestFinished-%d" % os.getpid())
-    with open(fname, "w") as f:
-        print("Test finished at: %s\n" % datetime.datetime.now().strftime("%Y-%m-%d-%H_%M_%S"), file=f)
-
     # Terminate the test suite if ${LLDB_TESTSUITE_FORCE_FINISH} is defined.
     # This should not be necessary now.
     if ("LLDB_TESTSUITE_FORCE_FINISH" in os.environ):