Fix clang test suite on Windows by reverting part of r347216

Otherwise, the clang analyzer tests fail on Windows when attempting to
unpickle AnalyzerTest objects in the worker processes. The pattern of,
add to path, import, remove from path, serialize, deserialize, doesn't
work. Once something gets added to the path, if we want to move it
across the wire for multiprocessing, we need to keep the module on
sys.path.

llvm-svn: 347254

lldb/lit/lit.cfg.py

@@ -11,6 +11,7 @@ from lit.llvm import llvm_config
 from lit.llvm.subst import FindTool
 from lit.llvm.subst import ToolSubst
 
+site.addsitedir(os.path.dirname(__file__))
 from helper import toolchain
 
 # name: The name of this test suite.

llvm/utils/lit/lit/TestingConfig.py

@@ -85,9 +85,7 @@ class TestingConfig:
         cfg_globals['config'] = self
         cfg_globals['lit_config'] = litConfig
         cfg_globals['__file__'] = path
-        original_sys_path = list(sys.path)
         try:
-            sys.path.insert(0, os.path.dirname(path))
             exec(compile(data, path, 'exec'), cfg_globals, None)
             if litConfig.debug:
                 litConfig.note('... loaded config %r' % path)
@@ -102,7 +100,6 @@ class TestingConfig:
             litConfig.fatal(
                 'unable to parse config file %r, traceback: %s' % (
                     path, traceback.format_exc()))
-        sys.path = original_sys_path
         self.finish(litConfig)
 
     def __init__(self, parent, name, suffixes, test_format,