openssl(_1_1): patch CVE-2019-1551

fetchpatch can't be used here and fetchurl from GitHub
like in PR #82928 has the risk of breaking the hash later;
fortunately the patches aren't too large.

(cherry picked from commit 2071e3be28ee0d6ec46056352c88b88f5c0d7f60)

pkgs/development/libraries/openssl/default.nix

@@ -161,6 +161,9 @@ in {
       (if stdenv.hostPlatform.isDarwin
        then ./1.1/use-etc-ssl-certs-darwin.patch
        else ./1.1/use-etc-ssl-certs.patch)
+
+      ./1.1/cve-2019-1551.patch
+      ./1.1/cve-2019-1551-improve.patch
     ];
     withDocs = true;
   };