Add some msxml3 tests.

diff --git a/configure.ac b/configure.ac
index 50b40d9..1b0a0c5 100644
--- a/configure.ac
+++ b/configure.ac
@@ -1571,6 +1571,7 @@
 dlls/msvideo/Makefile
 dlls/mswsock/Makefile
 dlls/msxml3/Makefile
+dlls/msxml3/tests/Makefile
 dlls/netapi32/Makefile
 dlls/netapi32/tests/Makefile
 dlls/newdev/Makefile