chainlint.pl: add parser to identify test definitions
Finish fleshing out chainlint.pl by adding ScriptParser, a parser which
scans shell scripts for tests defined by test_expect_success() and
test_expect_failure(), plucks the test body from each definition, and
passes it to TestParser for validation. It recognizes test definitions
not only at the top-level of test scripts but also tests synthesized
within compound commands such as loops and function.
Signed-off-by: Eric Sunshine <sunshine@sunshineco.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>