test: delete invalid http test

test: delete invalid http test

The test is no longer valid for the original scenario.

It now fails intermittently because of two other issues:
1. Since the client is only processing one readable event, the
   client request is not enough to keep the process alive and the
   process can exit before the desired events have been raised.
2. Reading just 1 byte is not enough to guarantee that the parser
   will eventually consume all the data and raise the desired
   parse error. I tried postponing the server.close() to address
   the issue at [1], but then the test just hangs sometimes.