[SYCL] Add copy/move ctors and assignment operators to sycl::detail::optional (intel#19834)

Currently, those are implicitly defined and perform bitwise copy of
Storage, that is incorrect if T has non-trivial copy ctors etc.
___
cherry-pick of:
intel@ffc2512

Patch-by: Alexandr-Konovalov <[email protected]>

Author: KornevNikita

sycl/include/sycl/detail/optional.hpp

@@ -22,6 +22,15 @@ template <typename T> class optional {
 public:
   constexpr optional() noexcept {}
   constexpr optional(std::nullopt_t) noexcept : optional() {}
+  constexpr optional(const optional &Other)
+      : ContainsValue{Other.ContainsValue} {
+    if (Other.ContainsValue)
+      new (Storage) T(Other.value());
+  }
+  constexpr optional(optional &&Other) : ContainsValue{Other.ContainsValue} {
+    new (Storage) T(std::move(Other.value()));
+    Other.ContainsValue = false;
+  }
 
   template <typename U>
   constexpr optional(const optional<U> &Other)
@@ -60,6 +69,21 @@ template <typename T> class optional {
     return *this;
   }
 
+  optional &operator=(const optional<T> &Other) {
+    if (has_value())
+      reinterpret_cast<T *>(Storage)->~T();
+    ContainsValue = Other.has_value();
+    new (Storage) T(Other.value());
+    return *this;
+  }
+  optional &operator=(optional<T> &&Other) noexcept {
+    if (has_value())
+      reinterpret_cast<T *>(Storage)->~T();
+    ContainsValue = Other.has_value();
+    new (Storage) T(std::move(Other.value()));
+    return *this;
+  }
+
   template <typename U> optional &operator=(const optional<U> &Other) {
     if (has_value())
       reinterpret_cast<T *>(Storage)->~T();