RFR: 8201178: Remove sun.nio.cs.FastCharsetProvider

[Claes Redestad]

Hi,

since JDK-8073152 sun.nio.cs.FastCharsetProvider is unused and can be 
removed.

Patch:
hg rm src/java.base/share/classes/sun/nio/cs/FastCharsetProvider.java

Bug: https://bugs.openjdk.java.net/browse/JDK-8201178

Thanks!

/Claes