[CUDA] Allow using -o with -fsyntax-only

-fsyntax-only breaks down CUDA compilation pipeline and make it look like
multiple independent subcompilations and that trips the multiple arguments check
when -o is specified.

We do want to allow -fsyntax-only to be used with otherwise unmodified clang
options as it's commonly used by various tooling.

Differential Revision: https://reviews.llvm.org/D133133