Add missing variable initialization.

Author: Alexandr-Konovalov

sycl/source/detail/cg.hpp

@@ -184,7 +184,7 @@ class CG {
           MSharedPtrStorage(SIH.MSharedPtrStorage),
           MRequirements(SIH.MRequirements),
           MEvents(SIH.MEvents.begin(), SIH.MEvents.end()) {}
-// The following storages are needed to ensure that arguments won't die
+    // The following storages are needed to ensure that arguments won't die
     // while we are using them.
     /// Storage for standard layout arguments.
     std::vector<std::vector<char>> MArgsStorage;

sycl/source/detail/handler_impl.hpp

@@ -73,13 +73,13 @@ class handler_impl {
   /// Shared pointer to the primary queue implementation. This is different from
   /// the queue associated with the handler if the corresponding submission is
   /// a fallback from a previous submission.
-  queue_impl *MSubmissionPrimaryQueue;
+  queue_impl *MSubmissionPrimaryQueue = nullptr;
 
   /// Shared pointer to the secondary queue implementation. Nullptr if no
   /// secondary queue fallback was given in the associated submission. This is
   /// equal to the queue associated with the handler if the corresponding
   /// submission is a fallback from a previous submission.
-  queue_impl *MSubmissionSecondaryQueue;
+  queue_impl *MSubmissionSecondaryQueue = nullptr;
 
   /// Bool stores information about whether the event resulting from the
   /// corresponding work is required.