RFR [9] 8146771: Remove unused CEFormatException and CEStreamExhausted from sun.misc

[Chris Hegarty]

These Exception types were used by the old character encoders/decoders
in sun.misc, that have since been removed, see 8144479 [1]. There is no
reason to keep these old Exception types.

$ hg rm src/java.base/share/classes/sun/misc/CEFormatException.java
$ hg rm src/java.base/share/classes/sun/misc/CEStreamExhausted.java

-Chris.

[1] https://bugs.openjdk.java.net/browse/JDK-8146771