Pass DynamicLookupInfo through VisibleDeclConsumers NFC

This commit adds a new type DynamicLookupInfo that provides information
about how a dynamic member lookup found a particular Decl. This is
needed to correctly handle KeyPath dynamic member lookups, but for now
just plumb it through everywhere.

lib/AST/ASTDemangler.cpp

@@ -1041,7 +1041,8 @@ ASTBuilder::findForeignTypeDecl(StringRef name,
 
     explicit Consumer(Demangle::Node::Kind kind) : ExpectedKind(kind) {}
 
-    void foundDecl(ValueDecl *decl, DeclVisibilityKind reason) override {
+    void foundDecl(ValueDecl *decl, DeclVisibilityKind reason,
+                   DynamicLookupInfo dynamicLookupInfo = {}) override {
       if (HadError) return;
       if (decl == Result) return;
       if (!Result) {