t3703: skip more tests using colons in file names on Windows

Use the same test and prerequisite as introduced in similar
fix in 650af7a.

Signed-off-by: Alex Riesen <raa.lkml@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

t/t3703-add-magic-pathspec.sh

@@ -38,17 +38,17 @@ cat >expected <<EOF
 add 'sub/foo'
 EOF
 
-test_expect_success 'a file with the same (long) magic name exists' '
-	: >":(icase)ha" &&
-	test_must_fail git add -n ":(icase)ha" &&
-	git add -n "./:(icase)ha"
-'
-
 if mkdir ":" 2>/dev/null
 then
 	test_set_prereq COLON_DIR
 fi
 
+test_expect_success COLON_DIR 'a file with the same (long) magic name exists' '
+	: >":(icase)ha" &&
+	test_must_fail git add -n ":(icase)ha" &&
+	git add -n "./:(icase)ha"
+'
+
 test_expect_success COLON_DIR 'a file with the same (short) magic name exists' '
 	: >":/bar" &&
 	test_must_fail git add -n :/bar &&