cmd/link: introduce and use peFile.writeFileHeader
cmd/link: introduce and use peFile.writeFileHeader

Change-Id: I1324b69ab9edb870589197fa601b5764634d42a4
Reviewed-on: https://go-review.googlesource.com/59427
Reviewed-by: Ian Lance Taylor <87e9c6d529889242b7e184afb632328636553ab4@golang.org>

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