tests: add merge-conflict branch for testrepo

Add a new branch that causes a merge conflict to `testrepo` so
that we are able to test merging in worktrees.

tests/iterator/workdir.c

@@ -613,6 +613,7 @@ void test_iterator_workdir__filesystem2(void)
 		"heads/ident",
 		"heads/long-file-name",
 		"heads/master",
+		"heads/merge-conflict",
 		"heads/packed-test",
 		"heads/subtrees",
 		"heads/test",
@@ -629,7 +630,7 @@ void test_iterator_workdir__filesystem2(void)
 
 	cl_git_pass(git_iterator_for_filesystem(
 		&i, "testrepo/.git/refs", NULL));
-	expect_iterator_items(i, 14, expect_base, 14, expect_base);
+	expect_iterator_items(i, 15, expect_base, 15, expect_base);
 	git_iterator_free(i);
 }
 

tests/refs/list.c

@@ -36,7 +36,7 @@ void test_refs_list__all(void)
 	/* We have exactly 12 refs in total if we include the packed ones:
 	 * there is a reference that exists both in the packfile and as
 	 * loose, but we only list it once */
-	cl_assert_equal_i((int)ref_list.count, 16);
+	cl_assert_equal_i((int)ref_list.count, 17);
 
 	git_strarray_free(&ref_list);
 }
@@ -51,7 +51,7 @@ void test_refs_list__do_not_retrieve_references_which_name_end_with_a_lock_exten
 		"144344043ba4d4a405da03de3844aa829ae8be0e\n");
 
 	cl_git_pass(git_reference_list(&ref_list, g_repo));
-	cl_assert_equal_i((int)ref_list.count, 16);
+	cl_assert_equal_i((int)ref_list.count, 17);
 
 	git_strarray_free(&ref_list);
 }

tests/revwalk/basic.c

@@ -177,7 +177,7 @@ void test_revwalk_basic__glob_heads_with_invalid(void)
 		/* walking */;
 
 	/* git log --branches --oneline | wc -l => 16 */
-	cl_assert_equal_i(18, i);
+	cl_assert_equal_i(19, i);
 }
 
 void test_revwalk_basic__push_head(void)