vendor: update buildkit to 664c2b469f19

Signed-off-by: CrazyMax <1951866+crazy-max@users.noreply.github.com>

vendor/google.golang.org/grpc/picker_wrapper.go

@@ -37,7 +37,6 @@ import (
 type pickerWrapper struct {
 	mu            sync.Mutex
 	done          bool
-	idle          bool
 	blockingCh    chan struct{}
 	picker        balancer.Picker
 	statsHandlers []stats.Handler // to record blocking picker calls
@@ -53,11 +52,7 @@ func newPickerWrapper(statsHandlers []stats.Handler) *pickerWrapper {
 // updatePicker is called by UpdateBalancerState. It unblocks all blocked pick.
 func (pw *pickerWrapper) updatePicker(p balancer.Picker) {
 	pw.mu.Lock()
-	if pw.done || pw.idle {
-		// There is a small window where a picker update from the LB policy can
-		// race with the channel going to idle mode. If the picker is idle here,
-		// it is because the channel asked it to do so, and therefore it is sage
-		// to ignore the update from the LB policy.
+	if pw.done {
 		pw.mu.Unlock()
 		return
 	}
@@ -210,23 +205,15 @@ func (pw *pickerWrapper) close() {
 	close(pw.blockingCh)
 }
 
-func (pw *pickerWrapper) enterIdleMode() {
-	pw.mu.Lock()
-	defer pw.mu.Unlock()
-	if pw.done {
-		return
-	}
-	pw.idle = true
-}
-
-func (pw *pickerWrapper) exitIdleMode() {
+// reset clears the pickerWrapper and prepares it for being used again when idle
+// mode is exited.
+func (pw *pickerWrapper) reset() {
 	pw.mu.Lock()
 	defer pw.mu.Unlock()
 	if pw.done {
 		return
 	}
 	pw.blockingCh = make(chan struct{})
-	pw.idle = false
 }
 
 // dropError is a wrapper error that indicates the LB policy wishes to drop the