Ensure test cache is not used for 'go test'

To quote 'go help test':

The idiomatic way to disable test caching explicitly is to use -count=1

Makefile

@@ -51,10 +51,10 @@ test_ruby:
 	bundle exec rspec --color --format d spec
 
 test_golang:
-	go test -cover -coverprofile=cover.out ./...
+	go test -cover -coverprofile=cover.out -count 1 ./...
 
 test_golang_race:
-	go test -race ./...
+	go test -race -count 1 ./...
 
 coverage: coverage_golang