[SYCL][ESIMD] Fix return value for test (#8992)

Right now it's returning 1 so the test is failing.

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Signed-off-by: Sarnie, Nick <[email protected]>

Author: sarnex

sycl/test-e2e/InvokeSimd/Spec/simd_mask_merge.cpp

@@ -100,5 +100,6 @@ int main() {
   }
 
   std::cout << (err_cnt > 0 ? "FAILED\n" : "Passed\n");
-  return err_cnt == 0;
+  assert(err_cnt == 0);
+  return 0;
 }