Enable memory debugging while testing

Pre 1.1.0, 'make test' would set the environment variable
OPENSSL_DEBUG_MEMORY to "on".  This got lost when translating the old
build files to the new templates.  This changes reintroduces that
variable.

Reviewed-by: Rich Salz <rsalz@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/1840)

Configurations/descrip.mms.tmpl

diff --git a/Configurations/descrip.mms.tmpl b/Configurations/descrip.mms.tmpl
index 3d221f5..15e0678 100644
--- a/Configurations/descrip.mms.tmpl
+++ b/Configurations/descrip.mms.tmpl
@@ -267,8 +267,10 @@
         DEFINE SRCTOP {- sourcedir() -}
         DEFINE BLDTOP {- builddir() -}
         DEFINE OPENSSL_ENGINES {- builddir("engines") -}
+        DEFINE OPENSSL_DEBUG_MEMORY "on"
         IF "$(VERBOSE)" .NES. "" THEN DEFINE VERBOSE "$(VERBOSE)"
         $(PERL) {- sourcefile("test", "run_tests.pl") -} $(TESTS)
+        DEASSIGN OPENSSL_DEBUG_MEMORY
         DEASSIGN OPENSSL_ENGINES
         DEASSIGN BLDTOP
         DEASSIGN SRCTOP