6888701 - Change all template java source files to a .java-template file suffix

[Ulf Zibis]

IMO you should add jdk/make/tools/CharsetMapping/*.java to the fix of 
Bug 6888701.

Additionally, I don't understand, why there is differing strategy for 
location of templates. E.g. jdk/make/tools/CharsetMapping/*.java files 
could be in jdk/src/share/classes/sun/nio/cs/.

-Ulf