Fix #76706: mbstring.http_output_conv_mimetypes is ignored

_php_mb_match_regex() is supposed to return != 0 on success, and 0 on
failure.  pcre2_match() returns >= 0 on success, and < 0 on failure.
We map the result accordingly.

Since this patch fixes four failing tests, there is no need to add
another.

Author: cmb69

NEWS

@@ -5,6 +5,7 @@ PHP                                                                        NEWS
 - mbstring:
   . Fixed bug #76704 (mb_detect_order return value varies based on argument
     type). (cmb)
+  . Fixed bug #76706 (mbstring.http_output_conv_mimetypes is ignored). (cmb)
 
 - phpdbg:
   . Fixed bug #76595 (phpdbg man page contains outdated information).

ext/mbstring/mbstring.c

@@ -1068,7 +1068,7 @@ static int _php_mb_match_regex(void *opaque, const char *str, size_t str_len)
 		php_error_docref(NULL, E_WARNING, "Cannot allocate match data");
 		return FAILURE;
 	}
-	res = pcre2_match(opaque, (PCRE2_SPTR)str, str_len, 0, 0, match_data, php_pcre_mctx());
+	res = pcre2_match(opaque, (PCRE2_SPTR)str, str_len, 0, 0, match_data, php_pcre_mctx()) >= 0;
 	php_pcre_free_match_data(match_data);
 
 	return res;