Added a new ValueObject type that will be used to freeze dry expression

results. The clang opaque type for the expression result will be added to the
Target's ASTContext, and the bytes will be stored in a DataBuffer inside
the new object. The class is named: ValueObjectConstResult

Now after an expression is evaluated, we can get a ValueObjectSP back that
contains a ValueObjectConstResult object.

Relocated the value object dumping code into a static function within
the ValueObject class instead of being in the CommandObjectFrame.cpp file
which is what contained the code to dump variables ("frame variables").

llvm-svn: 115578