[lworld] Duplicate/redundant CONSTANT_Class_info entry in constant pool

Given this program:

public primitive class X {
    Object o = new X.ref[0];
}

javac generates redundant Constant_Class_info entries as shown
by this extract of the constant pool:

Constant pool:
   #1 = Class #2 // X
   #2 = Utf8 X
   #3 = Class #2 // X
   #4 = Fieldref #1.#5 // X.o:Ljava/lang/Object;
   #5 = NameAndType #6:#7 // o:Ljava/lang/Object;
   #6 = Utf8 o

...

The entry at index is referred to by

this_class: #1 // X

while the entry at 3 is referenced by

anewarray #3 // class X

Basically, com.sun.tools.javac.jvm.PoolWriter#putClass(com.sun.tools.javac.code.Type) fails to recognize that there is no need to emit different
Constant_info entries for X.ref and X.val types - these entries are indistinguishable at the level of a Constant_info structure and so can be shared.