[JENKINS-15382] no longer only about UTF-8

(cherry picked from commit 59f0f32ff63d081475e5c691a8c932d98f688101)
[FIXED JENKINS-15382]

Revisiting the fix. Avoid parsing the entire text by only looking at the tail portion.

(cherry picked from commit 14d980c4377dc703df8db76f192de19246a0266e)
[JENKINS-15382] Forgot to close the file

(cherry picked from commit 43ecda6d2d4aba44144d12fb89ad1ed3e77bc7f3)
[JENKINS-15382] not sure which code is triggering animal sniffer violation

(cherry picked from commit f7671e621e374bc51a81ec75c056d15ee359093a)
[JENKINS-15382] removed Java 1.6 dependency

(cherry picked from commit 82404407f2c26b3b0509e392ec35dee8ea7dc571)
[FIXED JENKINS-19171] Identify user agent for Internet Explorer 11.

(cherry picked from commit a184ef54cd9da5b2e20ca0bc31c53e99c5793741)
[FIXED JENKINS-18775] Integrated XStream 1.4.4-jenkins-4 with attempted fix for race condition.

(cherry picked from commit 89c94dda875fba273d22451c540c2ad9e4ac0197)
[JENKINS-17248] Be robust against exceptions in ItemListener.onLoaded, since this could interrupt Jenkins startup.

(cherry picked from commit 4def416224074c611f41185bd4e2dd0b68bcba5d)