tidy-up: C and CI

- drop redundant casts for `CURL_UNCONST()` pointers (Windows).
- GHA/linux: delete redundant/dupe `-g` C flag in memory sanitizer job.
  Spotted-by: Daniel Stenberg
- examples/http2-upload: drop local macro.
- examples/http2-upload: drop leading underscore from union name.
- examples/http2-upload: drop interim macro.
- tests/server/util: reapply patch lost in a rebase.
- sync `main()` declarations across the codebase.

Closes #22559

projects/vms/report_openssl_version.c

@@ -39,7 +39,7 @@ unsigned long LIB$SET_SYMBOL(const struct dsc$descriptor_s *symbol,
                              const struct dsc$descriptor_s *value,
                              const unsigned long *table_type);
 
-int main(int argc, char **argv)
+int main(int argc, char *argv[])
 {
   void *libptr;
   const char *(*ssl_version)(int t);