t-reftable-basics: use if_test

t-reftable-basics: use if_test

The macro TEST takes a single expression.  If a test requires multiple
statements then they need to be placed in a function that's called in
the TEST expression.

Remove the overhead of defining and calling single-use functions by
using if_test instead.

Run the tests in the order of definition.  We can reorder them like that
because they are independent.  Technically this changes the output, but
retains the meaning of a full run and allows for easier review e.g. with
diff option --ignore-all-space.

Signed-off-by: René Scharfe <l.s.r@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>