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.

Change-Id: I8f8cb164848b4ddf6e891974deb2dc1d606487df
Reviewed-on: https://go-review.googlesource.com/c/gofrontend/+/213642
Reviewed-by: Cherry Zhang <cherryyz@google.com>
11 files changed