[clang-format][NFC] Remove extraneous newlines at end of test cases

Removes some 500 newlines (\n and \r\n) at the end of test cases in
FormatTest.cpp.

Also changes a few verifyFormat() to verifyNoChange() in tests
InsertNewlineAtEOF and WhitespaceSensitiveMacros as messUp() removes
trailing newlines as well.

Differential Revision: https://reviews.llvm.org/D158805