CI: add the grabpl build-backend command into the repo (#52673)

* Move the grabpl build-backend command and clean it up a bit

pkg/build/errutil/group.go

@@ -0,0 +1,61 @@
+package errutil
+
+import (
+	"context"
+	"log"
+	"sync"
+)
+
+type Group struct {
+	cancel  func()
+	wg      sync.WaitGroup
+	errOnce sync.Once
+	err     error
+}
+
+func GroupWithContext(ctx context.Context) (*Group, context.Context) {
+	ctx, cancel := context.WithCancel(ctx)
+	return &Group{cancel: cancel}, ctx
+}
+
+// Wait waits for any wrapped goroutines to finish and returns any error having occurred in one of them.
+func (g *Group) Wait() error {
+	log.Println("Waiting on Group")
+	g.wg.Wait()
+	if g.cancel != nil {
+		log.Println("Group canceling its context after waiting")
+		g.cancel()
+	}
+	return g.err
+}
+
+// Cancel cancels the associated context.
+func (g *Group) Cancel() {
+	log.Println("Group's Cancel method being called")
+	g.cancel()
+}
+
+// Wrap wraps a function to be executed in a goroutine.
+func (g *Group) Wrap(f func() error) func() {
+	g.wg.Add(1)
+	return func() {
+		defer g.wg.Done()
+
+		if err := f(); err != nil {
+			g.errOnce.Do(func() {
+				log.Printf("An error occurred in Group: %s", err)
+				g.err = err
+				if g.cancel != nil {
+					log.Println("Group canceling its context due to error")
+					g.cancel()
+				}
+			})
+		}
+	}
+}
+
+// Go wraps the provided function and executes it in a goroutine.
+func (g *Group) Go(f func() error) {
+	wrapped := g.Wrap(f)
+	go wrapped()
+}