misc/cgo/testcshared: cd into work directory before running android command
misc/cgo/testcshared: cd into work directory before running android command

Hopefully this will fix android build.

Maybe fixes #21513

Change-Id: I98f760562646f06b56e385c36927e79458465b92
Reviewed-on: https://go-review.googlesource.com/56790
Reviewed-by: Ian Lance Taylor <87e9c6d529889242b7e184afb632328636553ab4@golang.org>
Run-TryBot: Ian Lance Taylor <87e9c6d529889242b7e184afb632328636553ab4@golang.org>
TryBot-Result: Gobot Gobot <66cb808b70d30c07676d5e946fee83fd561249e5@golang.org>

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