[dev.regabi] cmd/compile: directly create go.map and go.track symbols

These symbols are implementation details and don't correspond to Go
source symbols, so directly create them as linker symbols and get rid
of their pseudo packages.

Passes toolstash -cmp w/ -gcflags=all=-abiwrap.

Change-Id: I2e97374c21f3e909f6d350f15e7a5ed3574cadf4
Reviewed-on: https://go-review.googlesource.com/c/go/+/284372


Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Cuong Manh Le <cuong.manhle.vn@gmail.com>
Trust: Matthew Dempsky <mdempsky@google.com>