t/t9NNN: allow local submodules

To prepare for the default value of `protocol.file.allow` to change to
"user", ensure tests that rely on local submodules can initialize them
over the file protocol.

Tests that interact with submodules a handful of times use
`test_config_global`.

Signed-off-by: Taylor Blau <me@ttaylorr.com>

t/t9304-fast-import-marks.sh

@@ -25,6 +25,7 @@ test_expect_success 'import with large marks file' '
 '
 
 test_expect_success 'setup dump with submodule' '
+	test_config_global protocol.file.allow always &&
 	git submodule add "$PWD" sub &&
 	git commit -m "add submodule" &&
 	git fast-export HEAD >dump

t/t9350-fast-export.sh

@@ -265,6 +265,7 @@ test_expect_success 'signed-tags=warn-strip' '
 
 test_expect_success 'setup submodule' '
 
+	test_config_global protocol.file.allow always &&
 	git checkout -f master &&
 	mkdir sub &&
 	(
@@ -290,6 +291,7 @@ test_expect_success 'setup submodule' '
 
 test_expect_success 'submodule fast-export | fast-import' '
 
+	test_config_global protocol.file.allow always &&
 	SUBENT1=$(git ls-tree master^ sub) &&
 	SUBENT2=$(git ls-tree master sub) &&
 	rm -rf new &&