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/unit1602.c

@@ -29,27 +29,30 @@
 
 #include <memdebug.h> /* LAST include file */
 
-static struct Curl_hash t1602_hash_static;
-
 static void t1602_mydtor(void *p)
 {
   int *ptr = (int *)p;
   free(ptr);
 }
 
-static CURLcode unit_setup(void)
+static CURLcode t1602_setup(struct Curl_hash *hash)
 {
-  Curl_hash_init(&t1602_hash_static, 7, Curl_hash_str,
+  Curl_hash_init(hash, 7, Curl_hash_str,
                  curlx_str_key_compare, t1602_mydtor);
   return CURLE_OK;
 }
 
-static void unit_stop(void)
+static void t1602_stop(struct Curl_hash *hash)
 {
-  Curl_hash_destroy(&t1602_hash_static);
+  Curl_hash_destroy(hash);
 }
 
-UNITTEST_START
+static CURLcode test_unit1602(char *arg)
+{
+  struct Curl_hash hash;
+
+  UNITTEST_BEGIN(t1602_setup(&hash))
+
   int *value;
   int *value2;
   int *nodep;
@@ -58,23 +61,23 @@ UNITTEST_START
   int key = 20;
   int key2 = 25;
 
-
   value = malloc(sizeof(int));
   abort_unless(value != NULL, "Out of memory");
   *value = 199;
-  nodep = Curl_hash_add(&t1602_hash_static, &key, klen, value);
+  nodep = Curl_hash_add(&hash, &key, klen, value);
   if(!nodep)
     free(value);
   abort_unless(nodep, "insertion into hash failed");
-  Curl_hash_clean(&t1602_hash_static);
+  Curl_hash_clean(&hash);
 
   /* Attempt to add another key/value pair */
   value2 = malloc(sizeof(int));
   abort_unless(value2 != NULL, "Out of memory");
   *value2 = 204;
-  nodep = Curl_hash_add(&t1602_hash_static, &key2, klen, value2);
+  nodep = Curl_hash_add(&hash, &key2, klen, value2);
   if(!nodep)
     free(value2);
   abort_unless(nodep, "insertion into hash failed");
 
-UNITTEST_STOP
+  UNITTEST_END(t1602_stop(&hash))
+}