cmd/go: fix TestIssue7573 for absolute paths in -L options
cmd/go: fix TestIssue7573 for absolute paths in -L options

Updates #20266.
Fixes #20664.

Change-Id: Ifca30409fc7971497efb6d84f3f98760157c2233
Reviewed-on: https://go-review.googlesource.com/45650
Reviewed-by: Austin Clements <7ea35d812706d9213868749011af1ed4fa2f6aa0@google.com>

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