[xray] Remove cl::sub from alias options

Currently running the xray tools generates a number of errors:

$ ./bin/llvm-xray
: for the   -k option: cl::alias must not have cl::sub(), aliased option's cl::sub() will be used!
: for the   -d option: cl::alias must not have cl::sub(), aliased option's cl::sub() will be used!
: for the   -o option: cl::alias must not have cl::sub(), aliased option's cl::sub() will be used!
: for the   -f option: cl::alias must not have cl::sub(), aliased option's cl::sub() will be used!
: for the   -s option: cl::alias must not have cl::sub(), aliased option's cl::sub() will be used!
: for the   -r option: cl::alias must not have cl::sub(), aliased option's cl::sub() will be used!
: for the   -p option: cl::alias must not have cl::sub(), aliased option's cl::sub() will be used!
: for the   -m option: cl::alias must not have cl::sub(), aliased option's cl::sub() will be used!
<snip>

Patch by Ryan Mansfield.

Differential Revision: https://reviews.llvm.org/D69386