Remove EnumTest that uses cpp1
Remove EnumTest that uses cpp1

Summary:
Currently Thrift tests are the last places that use cpp1 and compatibility mode, so I'm switching them to cpp2 and removing duplicates.

This tests cpp1 generated enums, we have the same test for cpp2 `EnumTestCpp2`.

Reviewed By: yfeldblum, stevegury

Differential Revision: D7224676

fbshipit-source-id: 82f6b835cdee148e84b605b0e6fa82639faba647

facebook/fbthrift,facebook/fbthrift,facebook/fbthrift,facebook/fbthrift,facebook/fbthrift,facebook/fbthrift,facebook/fbthrift,facebook/fbthrift,facebook/fbthrift