Several tests: cd inside subshell instead of around

Fixed all places where it was a straightforward change from cd'ing into a
directory and back via "cd .." to a cd inside a subshell.

Found these places with "git grep -w "cd \.\.".

Signed-off-by: Jens Lehmann <Jens.Lehmann@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
diff --git a/t/t7400-submodule-basic.sh b/t/t7400-submodule-basic.sh
index 9bda970..21b0839 100755
--- a/t/t7400-submodule-basic.sh
+++ b/t/t7400-submodule-basic.sh
@@ -413,12 +413,12 @@
 
 test_expect_success 'add submodules without specifying an explicit path' '
 	mkdir repo &&
-	cd repo &&
+	(cd repo &&
 	git init &&
 	echo r >r &&
 	git add r &&
-	git commit -m "repo commit 1" &&
-	cd .. &&
+	git commit -m "repo commit 1"
+	) &&
 	git clone --bare repo/ bare.git &&
 	cd addtest &&
 	git submodule add "$submodurl/repo" &&