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/ct_test.c b/test/ct_test.c
index 5deb758..9c46bb4 100644
--- a/test/ct_test.c
+++ b/test/ct_test.c
@@ -501,7 +501,7 @@
 }
 #endif
 
-int test_main(int argc, char *argv[])
+int setup_tests(void)
 {
 #ifndef OPENSSL_NO_CT
     if ((ct_dir = getenv("CT_DIR")) == NULL)
@@ -519,10 +519,8 @@
     ADD_TEST(test_encode_tls_sct);
     ADD_TEST(test_default_ct_policy_eval_ctx_time_is_now);
     ADD_TEST(test_ctlog_from_base64);
-
-    return run_tests(argv[0]);
 #else
     printf("No CT support\n");
-    return EXIT_SUCCESS;
 #endif
+    return 1;
 }