cmd/internal/obj/riscv: improve large branch/call/jump tests
Rework these tests such that they are built on all architectures and
actually executed when run on riscv64. This increases the likelihood
of catching code generation issues, especially those that impact
relocations. Also ensure that the generated assembly includes the
instruction sequence that is expected for the large branch/call/jump.
Change-Id: I15c40a439dd1d0d4ed189ab81697e93d82c4ef4d
Reviewed-on: https://go-review.googlesource.com/c/go/+/721621 Reviewed-by: Mark Ryan <markdryan@rivosinc.com> Reviewed-by: Mark Freeman <markfreeman@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com> Reviewed-by: Junyang Shao <shaojunyang@google.com>