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/t9100-git-svn-basic.sh

@@ -22,7 +22,7 @@ esac
 test_expect_success \
     'initialize git svn' '
 	mkdir import &&
-	cd import &&
+	(cd import &&
 	echo foo > foo &&
 	ln -s foo foo.link
 	mkdir -p dir/a/b/c/d/e &&
@@ -31,8 +31,8 @@ test_expect_success \
 	echo "zzz" > bar/zzz &&
 	echo "#!/bin/sh" > exec.sh &&
 	chmod +x exec.sh &&
-	svn_cmd import -m "import for git svn" . "$svnrepo" >/dev/null &&
-	cd .. &&
+	svn_cmd import -m "import for git svn" . "$svnrepo" >/dev/null
+	) &&
 	rm -rf import &&
 	git svn init "$svnrepo"'