compiler, runtime: stop using __go_runtime_error

compiler, runtime: stop using __go_runtime_error

    Use specific panic functions instead, which are mostly already in the
    runtime package.

    Also correct "defer nil" to panic when we execute the defer, rather
    than throw when we queue it.

    Reviewed-on: https://go-review.googlesource.com/c/gofrontend/+/213642

From-SVN: r279979