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>

t/t9105-git-svn-commit-diff.sh

@@ -6,10 +6,10 @@ test_description='git svn commit-diff'
 
 test_expect_success 'initialize repo' '
 	mkdir import &&
-	cd import &&
+	(cd import &&
 	echo hello > readme &&
-	svn_cmd import -m "initial" . "$svnrepo" &&
-	cd .. &&
+	svn_cmd import -m "initial" . "$svnrepo"
+	) &&
 	echo hello > readme &&
 	git update-index --add readme &&
 	git commit -a -m "initial" &&