Remove unused ax_port_*alloc() functions (esp8266#3482)

The ax_port_malloc, ax_port_calloc, ax_port_realloc, and ax_port_free
functions in WiFiClientSecure are not actually used by the AXTLS library.
It's directly using the library routines, and these function are never
used.  Remove these dead bits of code to make the axtls operation clearer.

libraries/ESP8266WiFi/src/WiFiClientSecure.cpp

@@ -657,53 +657,6 @@ extern "C" int __ax_get_file(const char *filename, uint8_t **buf)
 }
 extern "C" void ax_get_file() __attribute__ ((weak, alias("__ax_get_file")));
 
-
-#ifdef DEBUG_TLS_MEM
-#define DEBUG_TLS_MEM_PRINT(...) DEBUGV(__VA_ARGS__)
-#else
-#define DEBUG_TLS_MEM_PRINT(...)
-#endif
-
-extern "C" void* ax_port_malloc(size_t size, const char* file, int line)
-{
-    (void) file;
-    (void) line;
-    void* result = malloc(size);
-    if (result == nullptr) {
-        DEBUG_TLS_MEM_PRINT("%s:%d malloc %d failed, left %d\r\n", file, line, size, ESP.getFreeHeap());
-    }
-    if (size >= 1024) {
-        DEBUG_TLS_MEM_PRINT("%s:%d malloc %d, left %d\r\n", file, line, size, ESP.getFreeHeap());
-    }
-    return result;
-}
-
-extern "C" void* ax_port_calloc(size_t size, size_t count, const char* file, int line)
-{
-    void* result = ax_port_malloc(size * count, file, line);
-    memset(result, 0, size * count);
-    return result;
-}
-
-extern "C" void* ax_port_realloc(void* ptr, size_t size, const char* file, int line)
-{
-    (void) file;
-    (void) line;
-    void* result = realloc(ptr, size);
-    if (result == nullptr) {
-        DEBUG_TLS_MEM_PRINT("%s:%d realloc %d failed, left %d\r\n", file, line, size, ESP.getFreeHeap());
-    }
-    if (size >= 1024) {
-        DEBUG_TLS_MEM_PRINT("%s:%d realloc %d, left %d\r\n", file, line, size, ESP.getFreeHeap());
-    }
-    return result;
-}
-
-extern "C" void ax_port_free(void* ptr)
-{
-    free(ptr);
-}
-
 extern "C" void __ax_wdt_feed()
 {
     optimistic_yield(10000);