curlx: limit use of system allocators to the minimum possible

Clone a multibye conversion function into curlx/fopen, and use that
local copy from curlx/fopen functions. Adjust allocators in curlx/fopen
to use curl's in normal builds, and system allocators in TrackMemory
builds to avoid recursion.

This allows to switch curlx/multibyte functions to curl allocators in
all configurations, as they are no longer called by curlx/fopen, and
a recursive call can no longer happen.

After this patch the system allocator is only used in TrackMemory
Windows builds, within curlx `fopen`, `freopen`, `stat` and `open`
functions.

Also:
- test 1, 440, 767: raise allocation limitsto fit the extra allocations
  in Windows Unicode builds.
- replace all uses of `curlx_unicodefree()` macro with `curlx_free()`
  across the codebase.
- curlx/multibyte: delete `curlx_unicodefree()`.
- ldap: join Windows and non-Windows codepaths that became
  identical after moving from `curlx_unicodefree()` to `curlx_free()`.
- vauth: drop a strdup from standard to curl allocator since
  the original allocation is now already done by curl's.
- tool_doswin: drop now superfluous strdup from `FindWin32CACert()`.
- memanalyzer.pm: sync weirdo `calloc` log message with `malloc`'s.

Fixes #19748
Closes #19845

src/tool_doswin.c

@@ -593,11 +593,8 @@ CURLcode FindWin32CACert(struct OperationConfig *config,
 
   res_len = SearchPath(NULL, bundle_file, NULL, PATH_MAX, buf, &ptr);
   if(res_len > 0) {
-    char *mstr = curlx_convert_tchar_to_UTF8(buf);
-    tool_safefree(config->cacert);
-    if(mstr)
-      config->cacert = curlx_strdup(mstr);
-    curlx_unicodefree(mstr);
+    curlx_free(config->cacert);
+    config->cacert = curlx_convert_tchar_to_UTF8(buf);
     if(!config->cacert)
       result = CURLE_OUT_OF_MEMORY;
   }

src/tool_filetime.c

@@ -47,7 +47,7 @@ int getfiletime(const char *filename, curl_off_t *stamp)
                      (FILE_SHARE_READ | FILE_SHARE_WRITE |
                       FILE_SHARE_DELETE),
                      NULL, OPEN_EXISTING, 0, NULL);
-  curlx_unicodefree(tchar_filename);
+  curlx_free(tchar_filename);
   if(hfile != INVALID_HANDLE_VALUE) {
     FILETIME ft;
     if(GetFileTime(hfile, NULL, NULL, &ft)) {
@@ -113,7 +113,7 @@ void setfiletime(curl_off_t filetime, const char *filename)
                      (FILE_SHARE_READ | FILE_SHARE_WRITE |
                       FILE_SHARE_DELETE),
                      NULL, OPEN_EXISTING, 0, NULL);
-  curlx_unicodefree(tchar_filename);
+  curlx_free(tchar_filename);
   if(hfile != INVALID_HANDLE_VALUE) {
     curl_off_t converted = ((curl_off_t)filetime * 10000000) +
       116444736000000000;

src/tool_getparam.h

@@ -383,7 +383,7 @@ ParameterError parse_args(int argc, argv_item_t argv[]);
 
 #define convert_UTF8_to_tchar(ptr) curlx_convert_UTF8_to_wchar((ptr))
 #define convert_tchar_to_UTF8(ptr) curlx_convert_wchar_to_UTF8((ptr))
-#define unicodefree(ptr)           curlx_unicodefree(ptr)
+#define unicodefree(ptr)           curlx_free(ptr)
 
 #else