cmd/compile: use type. prefix on importpath symbol
cmd/compile: use type. prefix on importpath symbol

This ensures that importpath symbols are treated like other type data
and end up in the same section under all build modes.

Fixes: go test -buildmode=pie reflect

Change-Id: Ibb8348648e8dcc850f2424d206990a06090ce4c6
Reviewed-on: https://go-review.googlesource.com/22081
Run-TryBot: David Crawshaw <a2f0bf29257797dd66800b4fbb9945c3e216c004@golang.org>
TryBot-Result: Gobot Gobot <66cb808b70d30c07676d5e946fee83fd561249e5@golang.org>
Reviewed-by: Ian Lance Taylor <87e9c6d529889242b7e184afb632328636553ab4@golang.org>

linux-on-ibm-z/go,josharian/go,theif519/go,vsekhar/elastic-go,ImJasonH/go,ganboing/go-esx,suncycheng/go,ganboing/go-esx,cloudflare/go,nawawi/go,Cofyc/go,nawawi/go,akutz/go,theif519/go,vanloswang/go,momchil-velikov/go,polyverse-security/go,linux-on-ibm-z/go,momchil-velikov/go,polyverse-security/go,cloudflare/go,vanloswang/go,akutz/go,golang/go,4ad/go,4ad/go,nawawi/go,4ad/go,akutz/go,nawawi/go,goodlang/good,ImJasonH/go,josharian/go,Cofyc/go,vanloswang/go,josharian/go,vsekhar/elastic-go,derekmarcotte/go,momchil-velikov/go,cloudflare/go,codestation/go,vsekhar/elastic-go,linux-on-ibm-z/go,Cofyc/go,linux-on-ibm-z/go,cloudflare/go,derekmarcotte/go,cloudflare/go,vanloswang/go,codestation/go,nawawi/go,suncycheng/go,akutz/go,ImJasonH/go,theif519/go,momchil-velikov/go,suncycheng/go,codestation/go,polyverse-security/go,4ad/go,theif519/go,4ad/go,goodlang/good,goodlang/good,vsekhar/elastic-go,golang/go,josharian/go,momchil-velikov/go,theif519/go,josharian/go,derekmarcotte/go,CAFxX/go,suncycheng/go,CAFxX/go,4ad/go,4ad/go,derekmarcotte/go,polyverse-security/go,suncycheng/go,ganboing/go-esx,ImJasonH/go,polyverse-security/go,Cofyc/go,vsekhar/elastic-go,codestation/go,linux-on-ibm-z/go,Cofyc/go,suncycheng/go,CAFxX/go,CAFxX/go,4ad/go,ganboing/go-esx,ganboing/go-esx,derekmarcotte/go,christopher-henderson/Go,ganboing/go-esx,cloudflare/go,momchil-velikov/go,cloudflare/go,vanloswang/go,momchil-velikov/go,vanloswang/go,cloudflare/go,nawawi/go,theif519/go,ImJasonH/go,CAFxX/go,akutz/go,golang/go,josharian/go,josharian/go,linux-on-ibm-z/go,suncycheng/go,goodlang/good,vsekhar/elastic-go,golang/go,ImJasonH/go,momchil-velikov/go,CAFxX/go,codestation/go,ganboing/go-esx,ganboing/go-esx,josharian/go,akutz/go,nawawi/go,Cofyc/go,CAFxX/go,goodlang/good,derekmarcotte/go,ImJasonH/go,codestation/go,linux-on-ibm-z/go,derekmarcotte/go,vsekhar/elastic-go,linux-on-ibm-z/go,golang/go,polyverse-security/go,akutz/go,goodlang/good,akutz/go,goodlang/good,vanloswang/go,polyverse-security/go,golang/go,codestation/go,goodlang/good,golang/go,golang/go,ImJasonH/go,nawawi/go,theif519/go,suncycheng/go,derekmarcotte/go,polyverse-security/go,Cofyc/go,codestation/go,vsekhar/elastic-go,CAFxX/go,Cofyc/go,theif519/go,vanloswang/go