build: surface error when noticing test failure

'set -e' means exit immediately on error.

Previously, the presubmit from integration test may experience
false positive because the exit code from npm test is not being
captured.

This false positive is noticed in CL 649258 where kokoro test
failed but LUCI test passed.

This CL should fail due to go1.24 vet behavior change but should
pass if rebased CL 649475.

For #3533

Change-Id: Iee7d5d02c178b8655a81b088f914d65237f79834
Reviewed-on: https://go-review.googlesource.com/c/vscode-go/+/649635
Auto-Submit: Hongxiang Jiang <hxjiang@golang.org>
Reviewed-by: Robert Findley <rfindley@google.com>
kokoro-CI: kokoro <noreply+kokoro@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>

Author: h9jiang

build/integration_test.go

@@ -48,7 +48,9 @@ func TestIntegration(t *testing.T) {
 	// Use "npm config set color false" to disable npm color output globally,
 	// and because we cannot access the Mocha command directly in this script,
 	// we use env "FORCE_COLOR=0" to disable its color output.
-	script := `npm config set color false;
+	script := `set -e;
+
+npm config set color false;
 npm ci;
 
 echo "**** Set up virtual display ****";