The removed tests in LinkerTest were ported (or were previously
ported) to the new CommentFormatter framework in the CommentParserTest
class; some references to the LinkerTest class have been removed since
CommentParserTest is now the canonical location for these.
Cleaned up a bit more from the removed DummyLinker class as well
(I69689b2037269af3320b6203fc44755f93713489).
Followup-To: I69689b2037269af3320b6203fc44755f93713489
Change-Id: Ia743d13c4fe7f4e3e2bd11274895a261adbfd8e2
ab660966d2