[Turboprop] Avoid early/late graph trimming in TurboProp

The early/late graph trimming phases remove dead nodes from the graph,
however these dead nodes don't have significant impact on the quality of
the codegen or the performance of the rest of the pipeline.

BUG=v8:9684

Change-Id: I1e797b520accc19ea59f2a430433e5b489c10e47
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2897889Reviewed-by: Georg Neis <neis@chromium.org>
Commit-Queue: Ross McIlroy <rmcilroy@chromium.org>
Cr-Commit-Position: refs/heads/master@{#74640}

src/compiler/pipeline.cc

@@ -2645,8 +2645,10 @@ bool PipelineImpl::CreateGraph() {
   RunPrintAndVerify(InliningPhase::phase_name(), true);
 
   // Remove dead->live edges from the graph.
-  Run<EarlyGraphTrimmingPhase>();
-  RunPrintAndVerify(EarlyGraphTrimmingPhase::phase_name(), true);
+  if (!data->info()->IsTurboprop()) {
+    Run<EarlyGraphTrimmingPhase>();
+    RunPrintAndVerify(EarlyGraphTrimmingPhase::phase_name(), true);
+  }
 
   // Determine the Typer operation flags.
   {
@@ -3410,8 +3412,10 @@ void PipelineImpl::ComputeScheduledGraph() {
   // We should only schedule the graph if it is not scheduled yet.
   DCHECK_NULL(data->schedule());
 
-  Run<LateGraphTrimmingPhase>();
-  RunPrintAndVerify(LateGraphTrimmingPhase::phase_name(), true);
+  if (!data->info()->IsTurboprop()) {
+    Run<LateGraphTrimmingPhase>();
+    RunPrintAndVerify(LateGraphTrimmingPhase::phase_name(), true);
+  }
 
   Run<ComputeSchedulePhase>();
   TraceScheduleAndVerify(data->info(), data, data->schedule(), "schedule");