Revert "x86cpuid.pl: fix extended feature flags detection."

This reverts commit 514f1a783515e9beb73b759a483c078813cf8ba0.
crypto/bn/asm/x86_64-mont.pl: minor optimization.
(cherry picked from commit 72a158703bf2b33f4eba6920302941560f7a848d)
crypto/modes/asm/aesni-gcm-x86_64.pl: minor optimization.

Avoid occasional up to 8% performance drops.
(cherry picked from commit 7a1a12232a84621271bf808107f3be9a2df5121a)
Merge remote-tracking branch 'upstream/OpenSSL_1_0_2-stable' into HEAD
Fix compilation with no-ec and/or no-tlsext.
Use TLS version supplied by client when fingerprinting Safari.
Tidy up comments.