The change in commit v3.9.0-rc4~3^2 (VS: Improve workaround for CUDA
-Xcompiler placement bug, 2017-06-21) accidentally appended to the
`AdditionalOptions` as if it were a `;`-separated list, but it is
actually a command-line string. Append with a space instead.
While at it, fix the same problem for the `AdditionalOptions` added to
`CudaLink` by commit v3.9.0-rc3~1^2 (CUDA: When linking device code
suppress CUDA 8.0+ deprecation warnings, 2017-06-09).
Fixes: #17008
In commit v3.9.0-rc1~431^2~6 (VS: Place CUDA host compiler options in
proper project file fields, 2017-03-07) we worked around a bug in the
CUDA VS integration by dropping `AdditionalCompilerOptions`. However,
this silently drops `-Xcompiler=` options given by the user that don't
map to one of CudaCompile's dedicated settings. Improve the workaround
to instead put the remaining `AdditionalCompilerOptions` into the
`AdditionalOptions` field behind `-Xcompiler=` ourselves.
