Small fix.

(cherry picked from commit 55ef36a2968e4524aaf57b218ee80143414f54cf)
Fix warnings

(cherry picked from commit db92449f41a7b581713508989cc9e1f3f5daca3a)
[Http]: Cosmetic, remove some dead code.

The is no reason to ever invoke the callback on the ThreadPool,
it would in fact only cause trouble.

Marek's commit db92449f was correct, I removed the commented out
code and the no longer used method.

(cherry picked from commit 7cb33a4fcc594ea638240639872a39e3e50daa51)
[system] Don't terminate response reading on bad cookie value. Fixes #18868

(cherry picked from commit 09366779f094b37e0240c0bcd09c0b5a07fc2135)
[System] Ensure pinvoke into OXS/iOS CFNetwork framework (for proxy support) are 64bits safe

(cherry picked from commit 1355ca90df9fc95f9f28f698743e151c6438631c)
[Http]: Fix the loop in WebConnection.ReadHeaders().

We need to reset `gotStatus' each time we enter the outer loop or we
would attempt to interpret the status line as a header.

(cherry picked from commit 5428bdfb71817eff5d82e4fe57ccf554fc851764)
[Http]: Fix digest authentication (bug #18799).

We did not correctly parse key-value pairs without quotes in the
challenge.

(cherry picked from commit 5e33f9eccf13d6ef7bb675c1cfb9929f96aba786)