tests: always make bundles, adapt build and tests

Make test bundles the default. Drop non-bundle build mode.
Also do all the optimizations and tidy-ups this allows, simpler builds,
less bundle exceptions, streamlined build mechanics.

Also rework the init/deinit macro magic for unit tests. The new method
allows using unique init/deinit function names, and calling them with
arguments. This is in turn makes it possible to reduce the use of global
variables.

Note this drop existing build options `-DCURL_TEST_BUNDLES=` from cmake
and `--enable-test-bundles` / `--disable-test-bundles` from autotools.

Also:
- rename test entry functions to have unique names: `test_<testname>`
  This removes the last exception that was handled in the generator.
- fix `make dist` to not miss test sources with test bundles enabled.
- sync and merge `tests/mk-bundle.pl` into `scripts/mk-unity.pl`.
- mk-unity.pl: add `--embed` option and use it when `CURL_CLANG_TIDY=ON`
  to ensure that `clang-tidy` does not miss external test C sources.
  (because `clang-tidy` ignores code that's #included.)
- tests/unit: drop no-op setup/stop functions.
- tests: reduce symbol scopes, global macros, other fixes and tidy-ups.
- tool1621: fix to run, also fix it to pass.
- sockfilt: fix Windows compiler warning in certain unity include order,
  by explicitly including `warnless.h`.

Follow-up to 6897aeb105 #17468

Closes #17590

tests/unit/unit1600.c

@@ -26,28 +26,30 @@
 #include "urldata.h"
 #include "curl_ntlm_core.h"
 
-static CURL *t1600_easy;
-
-static CURLcode unit_setup(void)
+static CURLcode t1600_setup(CURL **easy)
 {
   CURLcode res = CURLE_OK;
 
   global_init(CURL_GLOBAL_ALL);
-  t1600_easy = curl_easy_init();
-  if(!t1600_easy) {
+  *easy = curl_easy_init();
+  if(!*easy) {
     curl_global_cleanup();
     return CURLE_OUT_OF_MEMORY;
   }
   return res;
 }
 
-static void unit_stop(void)
+static void t1600_stop(CURL *easy)
 {
-  curl_easy_cleanup(t1600_easy);
+  curl_easy_cleanup(easy);
   curl_global_cleanup();
 }
 
-UNITTEST_START
+static CURLcode test_unit1600(char *arg)
+{
+  CURL *easy;
+
+  UNITTEST_BEGIN(t1600_setup(&easy))
 
 #if defined(USE_NTLM) && (!defined(USE_WINDOWS_SSPI) || \
                           defined(USE_WIN32_CRYPTO))
@@ -65,11 +67,12 @@ UNITTEST_START
               "\x39\xaf\x87\xa6\x75\x0a\x7a\x00\xba\xa0"
               "\xd3\x4f\x04\x9e\xc1\xd0\x00\x00\x00\x00\x00", 21);
 
-/* !checksrc! disable LONGLINE 2 */
+  /* !checksrc! disable LONGLINE 2 */
   Curl_ntlm_core_mk_nt_hash("AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA", output);
 
   verify_memory(testp,
                 "\x36\x9d\xae\x06\x84\x7e\xe1\xc1\x4a\x94\x39\xea\x6f\x44\x8c\x65\x00\x00\x00\x00\x00", 21);
 #endif
 
-UNITTEST_STOP
+  UNITTEST_END(t1600_stop(easy))
+}