Revert "deprecate embedded browser (#12163)"

This reverts commit 736d8cbac4.

Bring contrib files for older contributions

buildscripts/race.sh

@@ -2,6 +2,6 @@
 
 set -e
 
-for d in $(go list ./...); do
+for d in $(go list ./... | grep -v browser); do
     CGO_ENABLED=1 go test -v -tags kqueue -race --timeout 100m "$d"
 done