t/t0000-basic: make sure subtests also use TEST_SHELL_PATH

3f824e9 (t/Makefile: introduce TEST_SHELL_PATH, 2017-12-08) allows for
setting a shell for running the tests, but the generated subtests weren't
updated.

Correct that and while at it update it to use write_script.

Signed-off-by: Carlo Marcelo Arenas Belón <[email protected]>
Acked-by: Jeff King <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>

Author: carenas

t/t0000-basic.sh

@@ -78,9 +78,7 @@ _run_sub_test_lib_test_common () {
 		# the sub-test.
 		sane_unset HARNESS_ACTIVE &&
 		cd "$name" &&
-		cat >"$name.sh" <<-EOF &&
-		#!$SHELL_PATH
-
+		write_script "$name.sh" "$TEST_SHELL_PATH" <<-EOF &&
 		test_description='$descr (run in sub test-lib)
 
 		This is run in a sub test-lib so that we do not get incorrect
@@ -95,15 +93,14 @@ _run_sub_test_lib_test_common () {
 		. "\$TEST_DIRECTORY"/test-lib.sh
 		EOF
 		cat >>"$name.sh" &&
-		chmod +x "$name.sh" &&
 		export TEST_DIRECTORY &&
 		TEST_OUTPUT_DIRECTORY=$(pwd) &&
 		export TEST_OUTPUT_DIRECTORY &&
 		if test -z "$neg"
 		then
 			./"$name.sh" "$@" >out 2>err
 		else
-			!  ./"$name.sh" "$@" >out 2>err
+			! ./"$name.sh" "$@" >out 2>err
 		fi
 	)
 }