ci: run go race tests in parallel over 8 containers (#16288)

* ci: run go race tests in parallel over 8 containers

Signed-off-by: Chris Goller <goller@gmail.com>

* ci: add timing hint for splitting go tests

Signed-off-by: Chris Goller <goller@gmail.com>

* ci: remove spurious grep

Signed-off-by: Chris Goller <goller@gmail.com>

* ci: mod=readonly should ignore unknown internal/promqltests path

Signed-off-by: Chris Goller <goller@gmail.com>

* ci: echo the packages tested

Signed-off-by: Chris Goller <goller@gmail.com>

* ci: remove readonly experiment

Signed-off-by: Chris Goller <goller@gmail.com>

* ci: filter promql internal tests

The promql internal tests has a special go.mod that shows
up in go list.  That directory cannot be tested.

Signed-off-by: Chris Goller <goller@gmail.com>

.circleci/config.yml

@@ -208,6 +208,7 @@ jobs:
       GOFLAGS: "-mod=readonly -p=2" # Go on Circle thinks 32 CPUs are available, but there aren't.
       TEST_RESULTS: /tmp/test-results
     working_directory: /go/src/github.com/influxdata/influxdb
+    parallelism: 8
     steps:
       - checkout
 
@@ -227,7 +228,14 @@ jobs:
       - install_rust_compiler
       - run: mkdir -p $TEST_RESULTS
       - run: make test-go # This uses the test cache so it may succeed or fail quickly.
-      - run: GOTRACEBACK=all GO111MODULE=on FLUX_PARSER_TYPE=rust CGO_LDFLAGS="$(cat .cgo_ldflags)" gotestsum --format standard-quiet --junitfile /tmp/test-results/gotestsum.xml -- -race -count=1 -tags 'libflux' ./...
+      - run:
+          name: parallel go race tests
+          command: |
+            set +e
+            # filter internal/promqltests because it has special go.mod
+            TESTFILES=$(go list ./... | grep -v internal/promqltests | circleci tests split --split-by=timings)
+            echo $TESTFILES
+            GOTRACEBACK=all GO111MODULE=on FLUX_PARSER_TYPE=rust CGO_LDFLAGS="$(cat .cgo_ldflags)" gotestsum --format standard-quiet --junitfile /tmp/test-results/gotestsum.xml -- -race -count=1 -tags 'libflux' $TESTFILES
       - save_cache:
           name: Saving GOCACHE
           key: influxdb-gocache-{{ .Branch }}-{{ .Revision }}