Revert "win32: don't run subprocess tests on Mingw32 platform"

This reverts commit 7ad9339e372fcd12d584684d7f52ac259604a4f4.

The error "Failed to execute helper program (No such file or directory)"
is due to broken glib installation, missing windows gspawn helpers.

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Message-Id: <20170104205722.26492-1-marcandre.lureau@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
diff --git a/configure b/configure
index 091ae05..1f2ee71 100755
--- a/configure
+++ b/configure
@@ -3079,7 +3079,7 @@
 
 # g_test_trap_subprocess added in 2.38. Used by some tests.
 glib_subprocess=yes
-if test "$mingw32" = "yes" || ! $pkg_config --atleast-version=2.38 glib-2.0; then
+if ! $pkg_config --atleast-version=2.38 glib-2.0; then
     glib_subprocess=no
 fi