RFR: 8186334: JarFile throws ArrayIndexOutOfBoundsException when the manifest contains certain characters

[Claes Redestad]

Hi,

this patch addresses an unfortunate regression where backtick characters
in a manifest can cause an AIOOBE.

Webrev: http://cr.openjdk.java.net/~redestad/8186334/jdk.00/
Bug: https://bugs.openjdk.java.net/browse/JDK-8186334

Basically an off-by-one issue during certain steps in the search algorithm,
meaning it is context dependent whether a backtick will trip on this issue
or not.

/Claes