[Turboprop] Remove DecompressionOptimization phase from TurboProp.

Reduces the overhead of mid-tier optimization without much impact on
mid-tier generated code performance.

BUG=v8:9684

Change-Id: I81889049f718ec2b18a805b11aab119754466c95
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2772611
Auto-Submit: Ross McIlroy <rmcilroy@chromium.org>
Commit-Queue: Santiago Aboy Solanes <solanes@chromium.org>
Reviewed-by: Santiago Aboy Solanes <solanes@chromium.org>
Cr-Commit-Position: refs/heads/master@{#73509}

src/compiler/pipeline.cc

@@ -2865,11 +2865,6 @@ bool PipelineImpl::OptimizeGraphForMidTier(Linkage* linkage) {
   Run<ScheduledMachineLoweringPhase>();
   RunPrintAndVerify(ScheduledMachineLoweringPhase::phase_name(), true);
 
-  // The DecompressionOptimizationPhase updates node's operations but does not
-  // otherwise rewrite the graph, thus it is safe to run on a scheduled graph.
-  Run<DecompressionOptimizationPhase>();
-  RunPrintAndVerify(DecompressionOptimizationPhase::phase_name(), true);
-
   data->source_positions()->RemoveDecorator();
   if (data->info()->trace_turbo_json()) {
     data->node_origins()->RemoveDecorator();