message: TFL: Fix Subgraph::context_ initialization.
  As more and more methods have been added to context_, having a default null initialization of context_ make it safer.
  context_ is a POD-struct so no default initializer. context_() will zero-initialize all the members.
diff: @@ -532,7 +532,7 @@ class Subgraph {
  // A pure C data structure used to communicate with the pure C plugin
  // interface. To avoid copying tensor metadata, this is also the definitive
  // structure to store tensors.
  - TfLiteContext context_;
  + TfLiteContext context_ = {};
  // A pointer to the external contexts (kTfLiteMaxExternalContexts) array that
  // sits inside the associated TFLite interpreter instance.
  