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/unit1396.c

@@ -23,34 +23,35 @@
  ***************************************************************************/
 #include "curlcheck.h"
 
-static CURL *hnd;
-
-static CURLcode unit_setup(void)
+static CURLcode t1396_setup(void)
 {
   CURLcode res = CURLE_OK;
-
   global_init(CURL_GLOBAL_ALL);
   return res;
 }
 
-static void unit_stop(void)
+static void t1396_stop(CURL *easy)
 {
-  if(hnd)
-    curl_easy_cleanup(hnd);
+  if(easy)
+    curl_easy_cleanup(easy);
   curl_global_cleanup();
 }
 
-struct test {
-  const char *in;
-  int inlen;
-  const char *out;
-  int outlen;
-};
-
-UNITTEST_START
+static CURLcode test_unit1396(char *arg)
 {
+  CURL *easy;
+
+  UNITTEST_BEGIN(t1396_setup())
+
+  struct test {
+    const char *in;
+    int inlen;
+    const char *out;
+    int outlen;
+  };
+
   /* unescape, this => that */
-  const struct test list1[]={
+  const struct test list1[] = {
     {"%61", 3, "a", 1},
     {"%61a", 4, "aa", 2},
     {"%61b", 4, "ab", 2},
@@ -66,7 +67,7 @@ UNITTEST_START
     {NULL, 0, NULL, 0} /* end of list marker */
   };
   /* escape, this => that */
-  const struct test list2[]={
+  const struct test list2[] = {
     {"a", 1, "a", 1},
     {"/", 1, "%2F", 3},
     {"a=b", 3, "a%3Db", 5},
@@ -81,11 +82,11 @@ UNITTEST_START
   };
   int i;
 
-  hnd = curl_easy_init();
-  abort_unless(hnd != NULL, "returned NULL!");
+  easy = curl_easy_init();
+  abort_unless(easy != NULL, "returned NULL!");
   for(i = 0; list1[i].in; i++) {
     int outlen;
-    char *out = curl_easy_unescape(hnd,
+    char *out = curl_easy_unescape(easy,
                                    list1[i].in, list1[i].inlen,
                                    &outlen);
 
@@ -101,7 +102,7 @@ UNITTEST_START
 
   for(i = 0; list2[i].in; i++) {
     int outlen;
-    char *out = curl_easy_escape(hnd, list2[i].in, list2[i].inlen);
+    char *out = curl_easy_escape(easy, list2[i].in, list2[i].inlen);
     abort_unless(out != NULL, "returned NULL!");
 
     outlen = (int)strlen(out);
@@ -113,5 +114,6 @@ UNITTEST_START
 
     curl_free(out);
   }
+
+  UNITTEST_END(t1396_stop(easy))
 }
-UNITTEST_STOP