hg: jdk/sandbox: 8231717: Improve performance of charset decoding when charset is always compactable

[chris.hegarty at oracle.com]

Changeset: 3968bf3673c5
Author:    aleonard
Date:      2019-10-10 10:28 +0100
URL:       https://hg.openjdk.java.net/jdk/sandbox/rev/3968bf3673c5

8231717: Improve performance of charset decoding when charset is always compactable
Reviewed-by: rriggs, redestad, alanb

! make/data/charsetmapping/SingleByte-X.java.template
! make/jdk/src/classes/build/tools/charsetmapping/SBCS.java
! src/java.base/share/classes/java/lang/StringCoding.java
! src/java.base/share/classes/sun/nio/cs/ArrayDecoder.java
! src/java.base/share/classes/sun/nio/cs/SingleByte.java