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/unit1651.c

@@ -25,20 +25,15 @@
 
 #include "vtls/x509asn1.h"
 
-static CURLcode unit_setup(void)
+static CURLcode test_unit1651(char *arg)
 {
-  return CURLE_OK;
-}
+  UNITTEST_BEGIN_SIMPLE
 
-static void unit_stop(void)
-{
-
-}
 #if defined(USE_GNUTLS) || defined(USE_SCHANNEL)
 
-/* cert captured from gdb when connecting to curl.se on October 26
-   2018 */
-static unsigned char cert[] = {
+  /* cert captured from gdb when connecting to curl.se on October 26
+     2018 */
+  static unsigned char cert[] = {
   0x30, 0x82, 0x0F, 0x5B, 0x30, 0x82, 0x0E, 0x43, 0xA0, 0x03, 0x02, 0x01, 0x02,
   0x02, 0x0C, 0x08, 0x77, 0x99, 0x2C, 0x6B, 0x67, 0xE1, 0x18, 0xD6, 0x66, 0x66,
   0x9E, 0x30, 0x0D, 0x06, 0x09, 0x2A, 0x86, 0x48, 0x86, 0xF7, 0x0D, 0x01, 0x01,
@@ -342,10 +337,8 @@ static unsigned char cert[] = {
   0x70, 0x77, 0x54, 0x57, 0x09, 0x03, 0x56, 0x4A, 0x33, 0x60, 0x00, 0x27, 0xFE,
   0xA7, 0xD7, 0xA9, 0xC4, 0xEC, 0x17, 0x17, 0x8D, 0x87, 0x70, 0x6B, 0x48, 0x88,
   0x61, 0x54, 0x4A, 0x2B, 0xB7, 0x6A, 0x12, 0x08, 0xFB,
-};
+  };
 
-UNITTEST_START
-{
   CURLcode result;
   const char *beg = (const char *)&cert[0];
   const char *end = (const char *)&cert[sizeof(cert)];
@@ -378,15 +371,9 @@ UNITTEST_START
     curl_easy_cleanup(data);
   }
   curl_global_cleanup();
-}
-UNITTEST_STOP
-
 #else
-
-UNITTEST_START
-{
-  puts("not tested since Curl_extract_certinfo() is not built-in");
-}
-UNITTEST_STOP
-
+  puts("not tested since Curl_extract_certinfo() is not built in");
 #endif
+
+  UNITTEST_END_SIMPLE
+}