cmd/compile: update dalgsym to use obj.LSym
cmd/compile: update dalgsym to use obj.LSym

Passes toolstash-check.

Change-Id: I00a8200370d56772f604a099654f9d838c4f62e2
Reviewed-on: https://go-review.googlesource.com/41405
Run-TryBot: Josh Bleecher Snyder <cdc248cc4d32e4fbfe04e45228163bcecd48a0b9@gmail.com>
Reviewed-by: Matthew Dempsky <e56ac2c500064424afac424d4b5e53bd0570a731@google.com>

polyverse-security/go,codestation/go,codestation/go,Cofyc/go,codestation/go,akutz/go,vsekhar/elastic-go,CAFxX/go,codestation/go,vsekhar/elastic-go,Cofyc/go,akutz/go,golang/go,nawawi/go,ImJasonH/go,akutz/go,josharian/go,polyverse-security/go,josharian/go,nawawi/go,CAFxX/go,ImJasonH/go,nawawi/go,golang/go,Cofyc/go,ImJasonH/go,derekmarcotte/go,akutz/go,derekmarcotte/go,codestation/go,CAFxX/go,polyverse-security/go,golang/go,golang/go,akutz/go,ImJasonH/go,ImJasonH/go,CAFxX/go,ImJasonH/go,derekmarcotte/go,CAFxX/go,derekmarcotte/go,akutz/go,josharian/go,cloudflare/go,vsekhar/elastic-go,codestation/go,polyverse-security/go,akutz/go,polyverse-security/go,cloudflare/go,nawawi/go,nawawi/go,golang/go,josharian/go,derekmarcotte/go,Cofyc/go,derekmarcotte/go,josharian/go,Cofyc/go,cloudflare/go,Cofyc/go,cloudflare/go,ImJasonH/go,vsekhar/elastic-go,akutz/go,nawawi/go,cloudflare/go,josharian/go,cloudflare/go,golang/go,Cofyc/go,vsekhar/elastic-go,cloudflare/go,codestation/go,ImJasonH/go,christopher-henderson/Go,josharian/go,polyverse-security/go,derekmarcotte/go,nawawi/go,polyverse-security/go,CAFxX/go,vsekhar/elastic-go,golang/go,codestation/go,CAFxX/go,nawawi/go,vsekhar/elastic-go,Cofyc/go,CAFxX/go,cloudflare/go,derekmarcotte/go,josharian/go,golang/go,polyverse-security/go,vsekhar/elastic-go