show-branch tests: rename the one "show-branch" test file

Rename the only *show-branch* test file to indicate that more tests
belong it in than just the one-off octopus test it now contains.

The test was initially added in ce567d1 (Add test to show that
show-branch misses out the 8th column, 2008-07-23) and
11ee57b (sort_in_topological_order(): avoid setting a commit flag,
2008-07-23). Those two add almost the same content, one with a
test_expect_success and the other a test_expect_failure (a bug being
tested for was fixed on one of the branches).

Signed-off-by: Ævar Arnfjörð Bjarmason <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>

Author: avar

t/t3202-show-branch-octopus.sh renamed to t/t3202-show-branch.sh

@@ -1,6 +1,6 @@
 #!/bin/sh
 
-test_description='test show-branch with more than 8 heads'
+test_description='test show-branch'
 
 GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME=main
 export GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME