rev-parse tests: add tests executed from a subdirectory

rev-parse tests: add tests executed from a subdirectory

t2027-worktree-list has an incorrect expectation for --git-common-dir
which has been adjusted and marked to expect failure.

Some of the tests added have been marked to expect failure.  These
demonstrate a problem with the way that some options to git rev-parse
behave when executed from a subdirectory of the main worktree.

[jes: fixed incorrect assumption that objects/ lives in the
worktree-specific git-dir (it lives in the common dir instead). Also
adjusted t1700 so that the test case does not *need* to be the last
one in that script.]

Signed-off-by: Michael Rappazzo <rappazzo@gmail.com>
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>