rustbuild: RISC-V is no longer an experimental LLVM target

This commit moves RISC-V from the experimental LLVM targets to the
regular LLVM targets. RISC-V was made non-experimental in
https://reviews.llvm.org/rL366399

I have also sorted the list of LLVM targets, and changed the code
around setting llvm_exp_targets (and its default) to match the code
setting llvm_targets (and its default), ensuring future changes to
the defaults, as LLVM targets become stable, affect as few places as
possible.

0 files changed, 0 insertions, 0 deletions