Makefile: run lint and tests with default garbage-collection (#5841)
Makefile: run lint and tests with default garbage-collection (#5841)

Setting GOGC=10 makes Go run garbage-collection every time the heap gets
10% bigger than it was before, which does keep the max size down but
slows down memory-intensive operations.

Since this was added for CircleCI, and we don't run those operations
on CircleCI any more, remove the setting.
grafana/loki,grafana/loki,grafana/loki,grafana/loki,grafana/loki,grafana/loki