cmake: extend target_ld_options() to support grouping of flags

Fixes #28456

This commit extends `target_ld_options()` with a NO_SPLIT flag.

Specifying `NO_SPLIT` will ensure that all linker flags will be applied
together when testing the compiler and linker.
This allows a caller to ensure that flags are tested together.

This fixes the RISC-V case where the flags `-mabi` and `-march` were
omitted because they were tested individually.

Note, the update of `target_ld_options()` will allow the same flag on
`zephyr_ld_options()`

Signed-off-by: Torsten Rasmussen <Torsten.Rasmussen@nordicsemi.no>