t1510-repo-setup: mark as untraceable with '-x'

't1510-repo-setup.sh' checks the stderr of nested function calls way
too many times, resulting in several failures when using '-x' tracing,
unless it's executed with a Bash version supporting BASH_XTRACEFD.

Maybe someday we will clear up this test script, but until then mark
it as 'test_untraceable'.

After this change

  make GIT_TEST_OPTS='-x --verbose-log' test

finally fully passes without setting TEST_SHELL_PATH to Bash.

Signed-off-by: SZEDER Gábor <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>

Author: szeder

t/t1510-repo-setup.sh

@@ -39,6 +39,10 @@ A few rules for repo setup:
 11. When user's cwd is outside worktree, cwd remains unchanged,
     prefix is NULL.
 "
+
+# This test heavily relies on the standard error of nested function calls.
+test_untraceable=UnfortunatelyYes
+
 . ./test-lib.sh
 
 here=$(pwd)