Update the test framework so that the need for test_main is removed.  Everything
that needed test_main now works using the same infrastructure as tests that used
register_tests.

This meant:
* renaming register_tests to setup_tests and giving it a success/failure return.
* renaming the init_test function to setup_test_framework.
* renaming the finish_test function to pulldown_test_framework.
* adding a user provided global_init function that runs before the test frame
    work is initialised.  It returns a failure indication that stops the stest.
* adding helper functions that permit tests to access their command line args.
* spliting the BIO initialisation and finalisation out from the test setup and
    teardown.
* hiding some of the now test internal functions.
* fix the comments in testutil.h

Reviewed-by: Richard Levitte <levitte@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/3953)
diff --git a/test/afalgtest.c b/test/afalgtest.c
index 40ea025..62dcdb2 100644
--- a/test/afalgtest.c
+++ b/test/afalgtest.c
@@ -1,5 +1,5 @@
 /*
- * Copyright 2016 The OpenSSL Project Authors. All Rights Reserved.
+ * Copyright 2016-2017 The OpenSSL Project Authors. All Rights Reserved.
  *
  * Licensed under the OpenSSL license (the "License").  You may not use
  * this file except in compliance with the License.  You can obtain a copy
@@ -85,21 +85,20 @@
 }
 #endif
 
-int main(int argc, char **argv)
+#ifndef OPENSSL_NO_ENGINE
+int global_init(void)
 {
-    int ret = 0;
-
-#ifdef OPENSSL_NO_ENGINE
-    setup_test();
-    ret = run_tests(argv[0]);
-#else
     ENGINE_load_builtin_engines();
 # ifndef OPENSSL_NO_STATIC_ENGINE
     OPENSSL_init_crypto(OPENSSL_INIT_ENGINE_AFALG, NULL);
 # endif
+    return 1;
+}
+#endif
 
-    setup_test();
-
+int setup_tests(void)
+{
+#ifndef OPENSSL_NO_ENGINE
     if ((e = ENGINE_by_id("afalg")) == NULL) {
         /* Probably a platform env issue, not a test failure. */
         TEST_info("Can't load AFALG engine");
@@ -108,9 +107,14 @@
         ADD_TEST(test_afalg_aes_128_cbc);
 # endif
     }
-    ret = run_tests(argv[0]);
-    ENGINE_free(e);
 #endif
 
-    return finish_test(ret);
+    return 1;
 }
+
+#ifndef OPENSSL_NO_ENGINE
+void cleanup_tests(void)
+{
+    ENGINE_free(e);
+}
+#endif