[Internal] org.eclipse.jdt.internal.compiler.lookup.SourceTypeBinding.memberTypes computation code could be simpler.

[srikanth-sankaran]

While working on #4823 I notice that the code and interaction between these methods:

org.eclipse.jdt.internal.compiler.lookup.SourceTypeBinding.memberTypes()
org.eclipse.jdt.internal.compiler.lookup.SourceTypeBinding.setMemberTypes(ReferenceBinding[])
org.eclipse.jdt.internal.compiler.lookup.SourceTypeBinding.sortedMemberTypes()

makes for somewhat complicated reading and can be simplified quite a bit.

In particular, it is not clear we need org.eclipse.jdt.internal.compiler.lookup.SourceTypeBinding.memberTypesSorted at all, this should/could be subsumed by TagBits.HasUnresolvedMemberTypes itself.

[srikanth-sankaran]

ReferenceBinding [] members = this.memberTypes = this.prototype.memberTypes();
		int membersLength = members == null ? 0 : members.length;
		this.memberTypes = new ReferenceBinding[membersLength];

Why are there two assignments to this.memberTypes here in org.eclipse.jdt.internal.compiler.lookup.SourceTypeBinding.memberTypes() ?