path/filepath: add a test case for EvalSymlinks error
path/filepath: add a test case for EvalSymlinks error

EvalSymlinks returns error if given path or its target path don't exist.
Add a test for future improvement.

Change-Id: Ic9a4aa5eaee0fe7ac523d54d8eb3132a11b380b3
Reviewed-on: https://go-review.googlesource.com/27330
Reviewed-by: Russ Cox <5ad239cb8a44f659eaaee0aa1ea5b94947abe557@golang.org>
Run-TryBot: Russ Cox <5ad239cb8a44f659eaaee0aa1ea5b94947abe557@golang.org>

josharian/go,Cofyc/go,christopher-henderson/Go,linux-on-ibm-z/go,golang/go,josharian/go,polyverse-security/go,derekmarcotte/go,polyverse-security/go,suncycheng/go,akutz/go,golang/go,CAFxX/go,josharian/go,linux-on-ibm-z/go,nawawi/go,golang/go,josharian/go,polyverse-security/go,akutz/go,codestation/go,cloudflare/go,linux-on-ibm-z/go,codestation/go,codestation/go,golang/go,akutz/go,suncycheng/go,nawawi/go,suncycheng/go,derekmarcotte/go,vsekhar/elastic-go,Cofyc/go,cloudflare/go,CAFxX/go,nawawi/go,golang/go,momchil-velikov/go,codestation/go,ImJasonH/go,goodlang/good,ImJasonH/go,goodlang/good,ImJasonH/go,goodlang/good,codestation/go,vsekhar/elastic-go,goodlang/good,momchil-velikov/go,ImJasonH/go,Cofyc/go,suncycheng/go,goodlang/good,cloudflare/go,momchil-velikov/go,derekmarcotte/go,ImJasonH/go,derekmarcotte/go,ImJasonH/go,derekmarcotte/go,akutz/go,nawawi/go,Cofyc/go,CAFxX/go,polyverse-security/go,golang/go,cloudflare/go,golang/go,goodlang/good,momchil-velikov/go,goodlang/good,cloudflare/go,derekmarcotte/go,CAFxX/go,suncycheng/go,josharian/go,codestation/go,vsekhar/elastic-go,cloudflare/go,Cofyc/go,akutz/go,codestation/go,cloudflare/go,vsekhar/elastic-go,linux-on-ibm-z/go,Cofyc/go,vsekhar/elastic-go,suncycheng/go,momchil-velikov/go,vsekhar/elastic-go,CAFxX/go,golang/go,josharian/go,akutz/go,vsekhar/elastic-go,CAFxX/go,josharian/go,codestation/go,cloudflare/go,polyverse-security/go,suncycheng/go,CAFxX/go,goodlang/good,momchil-velikov/go,ImJasonH/go,nawawi/go,akutz/go,momchil-velikov/go,polyverse-security/go,nawawi/go,momchil-velikov/go,linux-on-ibm-z/go,akutz/go,CAFxX/go,linux-on-ibm-z/go,josharian/go,polyverse-security/go,ImJasonH/go,derekmarcotte/go,polyverse-security/go,linux-on-ibm-z/go,nawawi/go,derekmarcotte/go,Cofyc/go,Cofyc/go,nawawi/go,linux-on-ibm-z/go,vsekhar/elastic-go,suncycheng/go