This MR is intended to fix incorrect parsing of HTTP requests when empty header values are present.
The issue is was due to asymmetric behavior of `http_parser` library, which in case of:
* non-empty header values : invokes callbacks with the pointer to the start of a value
* empty header values : invokes callbacks with pointer to the start of next header or section
Since HTTP server relies on this pointer (along with length of the value) to locate the end of a value, and replace the line terminators (CRLFs) with null characters, the second case needed to be handled correctly.
Closes IDFGH-1539
Closes https://github.com/espressif/esp-idf/issues/3803
Backports !5663
* Fixed regex constraints for parsing IP and other parameters from monitor log.
* httplib connection timeouts set
* Redundent tests (commented out earlier) have been removed from advanced_tests. These tests are already run during unit testing.
This introduces the following changes in the example test scripts :
* Dependency on python requests library removed in favor of httplib
* Bug fixed in the logic responsible for receiving and processing http chunked responses
* Default timeouts increased Note : Due to connectivity issues (between runner host and DUT) in the runner environment, some of the advanced_tests are being ignored. These tests are intended for verifying the expected limits of the http_server capabilities, and implement sending and receiving of large HTTP packets and malformed requests, running multiple parallel sessions, etc. It is advised that all these tests be run locally, when making changes or adding new features to this component.
