[SYCL][LIT] Add deleter func for test in buffer.cpp to avoid potentia…

[v-klochkov]

…l SegFault

Signed-off-by: Vyacheslav N Klochkov [email protected]

[v-klochkov]

This fix is a light version of the changes proposed here: #2591
It does not add buffer constructors.

Motivation for the change: SegFault on such trivial case on Linux:

#include <memory>
#include <iostream>
struct A {
  A() { std::cout << "Init\n"; }
  ~A() { std::cout << "Free\n"; }
};
int main() {
  { std::cout << "good1:\n"; std::shared_ptr<A[]> good1(new A[5]); }
  { std::cout << "good2:\n"; std::shared_ptr<A>   good2(new A[5], [](A *p) {delete[] p;}); }
  { std::cout << "baad1:\n"; std::shared_ptr<A>   baad1(new A[5]); }
  
  return 0;
}