[7u45] Codereview request for JDK-8022868 :missing codepage Cp290 at java runtime

[Xueming Shen]

Hi, please help approve

JDK-8022868: missing codepage Cp290 at java runtime

This is the backport of #6614237 [1]. The 7u-dev change is slightly
different for the IBM300 part (which is a dbcs charset).  Since additional work
(doublebyte related) has been done in jdk8, the code base of 7u and jdk8 is
slightly different. I took the quick pass of simply taking the generated
IBM300.java with small update (to fit into the jdk7u-dev version) and dropped
it directly into the sun/nio/cs/ext.

http://cr.openjdk.java.net/~sherman/8022868/webrev/
http://cr.openjdk.java.net/~sherman/8022868/closed

Thanks,
-Sherman

[1] http://hg.openjdk.java.net/jdk8/tl/jdk/rev/54f0ccdd9ad7