Allow not flusing denorms in operands

Allow not flusing denorms in operands

This fixes tests for denorm value flush to zero in Ceil(), Log(),
 Log2(), Sqrt(), Sqrt2() operations. The test was assuming, that
operands of denormal value are flushed before the operation, however
the specification does not require that:

"If the entry point is declared with the DenormFlushToZero execution mode then for the
affected instuctions the denormalized result must be flushed to zero and the denormalized
operands **may** be flushed to zero."

VK-GL-CTS Issue: 2242

Affects: dEQP-VK.spirv_assembly.instruction.compute.float_controls.*.input_args.*_denorm_flush_to_zero

Components: Vulkan

Change-Id: Iedeb0d18fde3749a83be3262dba5efabf365aea2