Always update checkrun status for terraform workflows

Why?
* Terraform workflows cannot cancel due to WaitForCancellation, so we might as well try to update the status of the checkrun.
* We also think this will help with the non determinism issues we are seeing where cancellations can occur at different than expected times on replay, causing the checkrun cache to be inaccurate, thus causing wrong calls to either create or update.

server/neptune/workflows/internal/pr/revision/processor.go

@@ -17,8 +17,9 @@ import (
 )
 
 const (
-	ReviewSignalID    = "pr-review"
-	CheckRunCancelled = "checkrun was cancelled"
+	ReviewSignalID             = "pr-review"
+	CheckRunCancelled          = "checkrun was cancelled"
+	NotifyAllCheckRunsChangeID = "notify-all-checkruns-always"
 )
 
 type TFWorkflow func(ctx workflow.Context, request terraform.Request) (terraform.Response, error)
@@ -72,9 +73,11 @@ func (p *Processor) Process(ctx workflow.Context, prRevision Revision) {
 	// Mark checkruns as aborted if the context was cancelled, this typically happens if revisions arrive in quick succession
 	defer func() {
 		if temporal.IsCanceledError(ctx.Err()) {
-			ctx, _ := workflow.NewDisconnectedContext(ctx)
-			p.markCheckRunsAborted(ctx, prRevision, roots)
-			return
+			version := workflow.GetVersion(ctx, NotifyAllCheckRunsChangeID, workflow.DefaultVersion, 1)
+			if version == workflow.DefaultVersion {
+				p.markCheckRunsAborted(ctx, prRevision, roots)
+				return
+			}
 		}
 
 		// At this point, all workflows should be successful, and we can mark combined plan check run as success
@@ -131,6 +134,9 @@ func (p *Processor) awaitChildTerraformWorkflows(ctx workflow.Context, futures [
 	selector := workflow.NewNamedSelector(ctx, "TerraformChildWorkflow")
 	ch := workflow.GetSignalChannel(ctx, state.WorkflowStateChangeSignal)
 	selector.AddReceive(ch, func(c workflow.ReceiveChannel, _ bool) {
+		// The parent workflow can be cancelled when a new revision is received, but we still would like to notify
+		// state of any of the terraform workflows which will finish regardless of parent cancellation.
+		ctx, _ := workflow.NewDisconnectedContext(ctx)
 		p.TFStateReceiver.Receive(ctx, c, roots)
 	})
 
@@ -182,7 +188,6 @@ func (p *Processor) markCombinedCheckRun(ctx workflow.Context, revision Revision
 
 func (p *Processor) markCheckRunsAborted(ctx workflow.Context, revision Revision, roots map[string]RootInfo) {
 	p.markCombinedCheckRun(ctx, revision, github.CheckRunCancelled, CheckRunCancelled)
-
 	for _, rootInfo := range roots {
 		ctx = workflow.WithRetryPolicy(ctx, temporal.RetryPolicy{
 			MaximumAttempts: 3,