t3205: finalize transitioning to using the branch name main

In 66713e8 (tests: prepare aligned mentions of the default branch
name, 2020-10-23), we started that transition, trying to prepare for a
time when `git init` would use that name for the initial branch.

Even if that time has not arrived, we can complete the transition by
making the test script independent of the default branch name. This also
allows us to drop the `PREPARE_FOR_MAIN_BRANCH` prereq from one test
case.

Signed-off-by: Johannes Schindelin <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>

Author: dscho

t/t3205-branch-color.sh

@@ -5,7 +5,8 @@ test_description='basic branch output coloring'
 
 test_expect_success 'set up some sample branches' '
 	test_commit foo &&
-	git update-ref refs/remotes/origin/master HEAD &&
+	git branch -M main &&
+	git update-ref refs/remotes/origin/main HEAD &&
 	git update-ref refs/heads/other HEAD
 '
 
@@ -19,16 +20,16 @@ test_expect_success 'set up some color config' '
 
 test_expect_success 'regular output shows colors' '
 	cat >expect <<-\EOF &&
-	* <CYAN>master<RESET>
+	* <CYAN>main<RESET>
 	  <BLUE>other<RESET>
-	  <YELLOW>remotes/origin/master<RESET>
+	  <YELLOW>remotes/origin/main<RESET>
 	EOF
 	git branch --color -a >actual.raw &&
 	test_decode_color <actual.raw >actual &&
 	test_cmp expect actual
 '
 
-test_expect_success PREPARE_FOR_MAIN_BRANCH 'verbose output shows colors' '
+test_expect_success 'verbose output shows colors' '
 	oid=$(git rev-parse --short HEAD) &&
 	cat >expect <<-EOF &&
 	* <CYAN>main               <RESET> $oid foo