This commit updates and refactors the AFL host test mock as follows:
- Isolates the mock so that it only relies on lwip component and linux stdlib headers
- Grouped all mock functions in 'esp32_mock.h/c'
- Updates the lwip esp32 port files to include 'esp32_mock.h' when building for linux
- Use host stdlib headers instead of xtensa stdlib headers
If silent assert configuration is enabled, LWIP asserts are now 'silent' also.
Also updates KConfig to note that LWIP asserts are also disabled when asserts
are disabled globally (this was already the behaviour, but the config item
suggested otherwise.)
Progress towards https://github.com/espressif/esp-idf/issues/5873
This caused some unsigned int prints out to be printed as singed integer which made the logs unreadable, for example sequence numbers in TCP packet headers
