go/types: exclude test/fixedbugs/issue7746.go from tests
go/types: exclude test/fixedbugs/issue7746.go from tests

This backports an anlogous change made to std repo go/types and
enables running the tests again in a reasonable amount of time.

Change-Id: Ied59f6788b7b180f34c918a3c94d50c892b15f32
Reviewed-on: https://go-review.googlesource.com/10467
Reviewed-by: Alan Donovan <7069e9552f9d110b0a0f326b96f22f63fb99dfc1@google.com>

jdhenke/tools,sshetty10/tools,cmars/tools,sshetty10/tools,springning/tools,nicot/tools,magiccao/tools,runcom/tools,josharian/tools,jdhenke/tools,matryer/tools,cmars/tools,josharian/tools,cw2018/tools,argandas/tools,syreclabs/go-tools,magiccao/tools,sshetty10/tools,cmars/tools,magiccao/tools,nicot/tools,springning/tools,matryer/tools,glasser/golang-tools,syreclabs/go-tools,josharian/tools,jdhenke/tools,golang/tools,cw2018/tools,cw2018/tools,springning/tools,jdhenke/tools,springning/tools,syreclabs/go-tools,nicot/tools,syreclabs/go-tools,matryer/tools,matryer/tools,golang/tools,cmars/tools,nicot/tools,argandas/tools,runcom/tools,golang/tools,syreclabs/go-tools,glasser/golang-tools,cw2018/tools,golang/tools,golang/tools,glasser/golang-tools,runcom/tools,argandas/tools,magiccao/tools,runcom/tools,argandas/tools,josharian/tools,sshetty10/tools,glasser/golang-tools,syreclabs/go-tools