RFR - 8212975 - ClassDesc should have a full name method

[Jim Laskey]

Please review the webrev below.

Though generally useful for debugging ClassDesc (or using Class::forName), ClassDesc::fullDisplayName allows compiler devs to use a ClassDesc directly to optimally add classes to the symbol table.

Past:

	ClassDesc cd = ...
	String className = cd.packageName().isEmpty() ? cd.displayName() : cd.packageName() + "." + cd.displayName();
	Symbol classSym = names.fromString(className);

Future:

	ClassDesc cd = ...
	String className = cd.fullDisplayName();
	Symbol classSym = names.fromString(className);

JBS: https://bugs.openjdk.java.net/browse/JDK-8212975
webrev: http://cr.openjdk.java.net/~jlaskey/8212975/webrev/index.html