Volatile-memory-accces OpenCL target

cc @jdsteve2

Use as

from loopy.target.pyopencl import VolatileMemPyOpenCLTarget
knl = lp.make_kernel(
    ...,
    target=VolatileMemPyOpenCLTarget())

enabled an automatic merge when the pipeline for 50f1c8b6 succeeds

changed title from Volatile OpenCL target to Volatile-memory-accces OpenCL target

changed the description

merged

mentioned in commit ef8e4b56

@inducer Thank you!