mingw: fix t9700's assumption about directory separators

This test assumed that there is only one directory separator (the
forward slash), not two equivalent directory separators.
However, on Windows, the back slash and the forward slash *are*
equivalent.

Let's paper over this issue by converting the backward slashes to
forward ones in the test that fails with MSYS2 otherwise.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

t/t9700/test.pl

@@ -33,7 +33,7 @@ BEGIN
 is($r->config_int("test.nonexistent"), undef, "config_int: nonexistent");
 ok($r->config_bool("test.booltrue"), "config_bool: true");
 ok(!$r->config_bool("test.boolfalse"), "config_bool: false");
-is($r->config_path("test.path"), $r->config("test.pathexpanded"),
+is($r->config_path("test.path") =~ s/\\/\//gr, $r->config("test.pathexpanded"),
    "config_path: ~/foo expansion");
 is_deeply([$r->config_path("test.pathmulti")], ["foo", "bar"],
    "config_path: multiple values");