Move the second instance of TestUniqueTypes.py to a unique file

name.  lldb-dotest.py errors out if two tests have the same filename.

diff --git a/lldb/test/API/lang/cpp/unique-types/TestUniqueTypes.py b/lldb/test/API/lang/cpp/unique-types/TestUniqueTypes2.py
similarity index 100%
rename from lldb/test/API/lang/cpp/unique-types/TestUniqueTypes.py
rename to lldb/test/API/lang/cpp/unique-types/TestUniqueTypes2.py