Overhaul coverage setup

ci/test-coverage.sh

@@ -0,0 +1,40 @@
+#!/usr/bin/env bash
+set -e
+
+cd "$(dirname "$0")/.."
+
+annotate() {
+  ${BUILDKITE:-false} && {
+    buildkite-agent annotate "$@"
+  }
+}
+
+affectedFiles="$(buildkite-agent meta-data get affected_files)"
+echo "Affected files in this PR: $affectedFiles"
+if [[ ! ":$affectedFiles:" =~ \.rs: ]]; then
+  annotate --style info --context coverage-info \
+    "Coverage skipped as no .rs files were modified"
+  exit 0
+fi
+
+source ci/upload-ci-artifact.sh
+ci/version-check-with-upgrade.sh nightly
+
+scripts/coverage.sh
+
+report=coverage-"${BUILDKITE_COMMIT:0:9}".tar.gz
+mv target/cov/report.tar.gz "$report"
+upload-ci-artifact "$report"
+annotate --style success --context lcov-report \
+  "lcov report: <a href=\"artifact://$report\">$report</a>"
+
+echo "--- codecov.io report"
+if [[ -z "$CODECOV_TOKEN" ]]; then
+  echo "^^^ +++"
+  echo CODECOV_TOKEN undefined, codecov.io upload skipped
+else
+  bash <(curl -s https://codecov.io/bash) -X gcov -f target/cov/lcov.info
+
+  annotate --style success --context codecov.io \
+    "CodeCov report: https://codecov.io/github/solana-labs/solana/commit/${BUILDKITE_COMMIT:0:9}"
+fi