enqueue an unmap command but not call anly blocking API may cause define behavior

https://github.com/KhronosGroup/OpenCL-CTS/blob/bb604702a5c34e71697f306b693e812b288828c6/test_conformance/math_brute_force/unary_double.cpp#L307

After clFlush, the memory object processed by unmap(host command) may be released prematurely.

Start with test_conformance/math_brute_force/unary_double.cpp around line 307 and trace the clFlush, unmap, and memory-object lifetime involved. Determine the expected behavior when no blocking API is called, then add or update coverage so the premature release is prevented and the relevant conformance test passes.

Written by the indexing model from the issue text.