t4214: generate expect in their own test cases

t4214: generate expect in their own test cases

Before, the expect files of the test case were being generated in the
setup method. However, it would make more sense to generate these files
within the test cases that actually use them so that it's obvious to
future readers where the expected values are coming from.

Move the generation of the expect files in their own respective test
cases.

While we're at it, we want to establish a pattern in this test suite
that, firstly, a non-colored test case is given then, immediately after,
the colored version is given.

Switch test cases "log --graph with tricky octopus merge, no color" and
"log --graph with tricky octopus merge with colors" so that the "no
color" version appears first.

This patch is best viewed with `--color-moved`.

Signed-off-by: Denton Liu <liu.denton@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>