[lldb] Remove unnecessary use of computeExtendedNominal

This doesn't appear to be necessary anymore, we're attempting to
reconstruct a VarDecl from a previous evaluation, but AFAICT that
would imply that we've already correctly resolved the type. But more
importantly, this wouldn't be correct anyway since it wouldn't handle
cases where resolving the extension relies on other extensions being
bound for e.g nested types.

Author: hamishknight

lldb/source/Plugins/ExpressionParser/Swift/SwiftASTManipulator.cpp

@@ -846,15 +846,6 @@ GetPatternBindingForVarDecl(swift::VarDecl *var_decl,
   swift::NamedPattern *named_pattern =
       swift::NamedPattern::createImplicit(ast_context, var_decl);
 
-  // Since lldb does not call bindExtensions, must ensure that any enclosing
-  // extension is bound
-  for (auto *context = containing_context; context;
-       context = context->getParent()) {
-    if (auto *d = context->getAsDecl()) {
-      if (auto *ext = swift::dyn_cast<swift::ExtensionDecl>(d))
-        ext->computeExtendedNominal();
-    }
-  }
   swift::Type type = containing_context->mapTypeIntoContext(
       var_decl->getInterfaceType());
   swift::TypedPattern *typed_pattern =