Character, Byte, Short valueOf instead of new instance

[Andrej Golovnin]

Hi Pavel,

> Thanks a lot! I've separated out all the changes from the 'jdk.internal.org.objectweb.asm' package. So I'll update both threads with new webrevs.
> 
> http://cr.openjdk.java.net/~prappo/8048874/webrev.02

Looks good to me.

@Otávio: Could you please submit the ASM related changes to the ASM project [1]? Thanks!

Best regards,
Andrej Golovnin

[1] http://asm.ow2.org/