Update to latest Clar
Update cl_assert_equal_sz to be nicer

This makes the size_t comparison test nicer (assuming that the
values are actually not using the full length), and converts
some cases that were using it for pointer comparison to use the
macro that is designed for pointer comparison.
Add cl_repo_set_bool and cleanup tests

This adds a helper function for the cases where you want to
quickly set a single boolean config value for a repository.
This allowed me to remove a lot of code.
Add has_cr_in_index check to CRLF filter

This adds a check to the drop_crlf filter path to check it the
file in the index already has a CR in it, in which case this will
not drop the CRs from the workdir file contents.

This uncovered a "bug" in `git_blob_create_fromworkdir` where the
full path to the file was passed to look up the attributes instead
of the relative path from the working directory root.  This meant
that the check in the index for a pre-existing entry of the same
name was failing.
Added some tests for issue #1397

Signed-off-by: Sven Strickroth <email@cs-ware.de>
Test fixes and cleanup

This fixes some places where the new tests were leaving the test
area in a bad state or were freeing data they should not free.
It also removes code that is extraneous to the core issue and
fixes an invalid SHA being looked up in one of the tests (which
was failing, but for the wrong reason).