Improve text matching in OutputSpec, fixing some failing Windows tests

Improve text matching in OutputSpec, fixing some failing Windows tests

Some Java 14 text block tests failed on Windows because a
StringTokenizer was used to split by LF, but the Windows line
separator is CR+LF. Because a multi-line string ending with CR+LF is
printed via 'System.out.println' in the test code, another CR+LF is
added to the output, resulting in trailing CR+LF+CR+LF. Hence, between
the two LFs, the tokenizer actually found an additional line consisting
of CR (only on Windows, of course). Despite each line token actually
containing a trailing CR token, that did not matter much because
'String.trim' was used everywhere before comparing values.

Anyway, the improved OutputSpec uses text.trim().split("\\s*\n\\s*"),
which takes care of leading/trailing whitespace both around the whole
output and for each separate line.

Signed-off-by: Alexander Kriegisch <Alexander@Kriegisch.name>