hg: jdk/jdk: 8166339: Code conversion working behavior was changed for x-IBM834

[xueming.shen at oracle.com]

Changeset: 08b5eb52ccfd
Author:    sherman
Date:      2018-01-31 08:42 -0800
URL:       http://hg.openjdk.java.net/jdk/jdk/rev/08b5eb52ccfd

8166339: Code conversion working behavior was changed for x-IBM834
Reviewed-by: coffeys

! src/java.base/share/classes/sun/nio/cs/DoubleByte.java
! test/jdk/sun/nio/cs/TestCp834_SBCS.java