[lldb] Remove errant call to SBReproducer.SetWorkingDirectory

The old reproducer functionality has been removed. Remove this call as
it's now just a NO-OP.

(cherry picked from commit 0016f47)

Author: JDevlieghere

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

@@ -553,7 +553,6 @@ def setUpClass(cls):
         if traceAlways:
             print("Change dir to:", full_dir, file=sys.stderr)
         os.chdir(full_dir)
-        lldb.SBReproducer.SetWorkingDirectory(full_dir)
 
         # Set platform context.
         cls.platformContext = lldbplatformutil.createPlatformContext()