SYCL: Shorten mangled kernel name types

SYCL: Shorten mangled kernel name types

Because they are used, for example, in the profiler output, and long
names make it hard to read.

Before:
- _ZTSZZL18isDeviceFunctionalRKN2cl4sycl6deviceEPNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEEENK3
- _ZTSN3gmx18LeapFrogKernelNameILNS_18NumTempScaleValuesE0ELNS_19VelocityScalingTypeE0EEE
- _ZTSN5Nbnxm15NbnxmKernelNameILb0ELb1ELNS_8ElecTypeE0ELNS_7VdwTypeE1EEE
- _ZTSN5Nbnxm24NbnxmKernelPruneOnlyNameILb1EEE

After:
- _ZTS11DummyKernel
- _ZTS14LeapFrogKernelILN3gmx18NumTempScaleValuesE2ELNS0_19VelocityScalingTypeE1EE
- _ZTS11NbnxmKernelILb0ELb1ELN5Nbnxm8ElecTypeE0ELNS0_7VdwTypeE1EE
- _ZTS20NbnxmKernelPruneOnlyILb1EE

Can be shortened further by casting enums to integers in template
arguments, but not sure it will improve readability much.