Make it possible to disable building and running tests

Reviewed-by: NRich Salz <rsalz@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/1514)

Configure

@@ -401,6 +401,7 @@ my @disablables = (
     "ssl-trace",
     "static-engine",
     "stdio",
+    "tests",
     "threads",
     "tls",
     "ts",

INSTALL

@@ -412,6 +412,9 @@
                    the OpenSSL tests also use the command line applications the
                    tests will also be skipped.
 
+  no-tests
+                   Don't build test programs or run any test.
+
   no-threads
                    Don't try to build with support for multi-threaded
                    applications.