[DEBUGINFO] [LLDB] Add support for generating debug-info for structured...

[DEBUGINFO] [LLDB] Add support for generating debug-info for structured bindings of structs and arrays

Currently we are not emitting debug-info for all cases of structured bindings a
C++17 feature which allows us to bind names to subobjects in an initializer.

A structured binding is represented by a DecompositionDecl AST node and the
binding are represented by a BindingDecl. It looks the original implementation
only covered the tuple like case which be represented by a DeclRefExpr which
contains a VarDecl.

If the binding is to a subobject of the struct the binding will contain a
MemberExpr and in the case of arrays it will contain an ArraySubscriptExpr.
This PR adds support emitting debug-info for the MemberExpr and ArraySubscriptExpr
cases as well as llvm and lldb tests for these cases as well as the tuple case.

Differential Revision: https://reviews.llvm.org/D119178