Revert "[turbofan] Add performance counters for speculation mode change"

This reverts commit ce2a9e16.

Reason for revert: Breaks all gpu bots, e.g.:
https://build.chromium.org/p/client.v8.fyi/builders/Linux%20Release%20%28NVIDIA%29/builds/4628

Original change's description:
> [turbofan] Add performance counters for speculation mode change
> 
> Bug: v8:7127, v8:7216
> Change-Id: I57f8bc3f486c53b11475bd174961c4547bb07b04
> Reviewed-on: https://chromium-review.googlesource.com/827073
> Commit-Queue: Sigurd Schneider <sigurds@chromium.org>
> Reviewed-by: Benedikt Meurer <bmeurer@chromium.org>
> Reviewed-by: Michael Hablich <hablich@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#50121}

TBR=sigurds@chromium.org,hablich@chromium.org,bmeurer@chromium.org

Change-Id: Ic658699a3c267758b925c4a6832992a638125d27
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: v8:7127, v8:7216
Reviewed-on: https://chromium-review.googlesource.com/828874Reviewed-by: Michael Achenbach <machenbach@chromium.org>
Commit-Queue: Michael Achenbach <machenbach@chromium.org>
Cr-Commit-Position: refs/heads/master@{#50125}

src/counters.h

@@ -1088,9 +1088,7 @@ class RuntimeCallTimerScope {
      20)                                                                       \
   HR(wasm_lazy_compilation_throughput, V8.WasmLazyCompilationThroughput, 1,    \
      10000, 50)                                                                \
-  HR(compile_script_cache_behaviour, V8.CompileScript.CacheBehaviour, 0, 19,   \
-     20)                                                                       \
-  HR(speculation_mode_change, V8.SpeculationModeChange, 0, 1, 2)
+  HR(compile_script_cache_behaviour, V8.CompileScript.CacheBehaviour, 0, 19, 20)
 
 #define HISTOGRAM_TIMER_LIST(HT)                                               \
   /* Garbage collection timers. */                                             \

src/deoptimizer.cc

@@ -3860,13 +3860,8 @@ void TranslatedState::DoUpdateFeedback() {
   if (!feedback_vector_handle_.is_null()) {
     CHECK(!feedback_slot_.IsInvalid());
     isolate()->CountUsage(v8::Isolate::kDeoptimizerDisableSpeculation);
-    isolate()->counters()->speculation_mode_change()->AddSample(
-        static_cast<int>(SpeculationModeChange::kSetSpeculationDisallow));
     CallICNexus nexus(feedback_vector_handle_, feedback_slot_);
     nexus.SetSpeculationMode(SpeculationMode::kDisallowSpeculation);
-  } else {
-    isolate()->counters()->speculation_mode_change()->AddSample(
-        static_cast<int>(SpeculationModeChange::kNoSpeculationModeChange));
   }
 }
 

src/deoptimizer.h

@@ -1041,11 +1041,6 @@ class DeoptimizedFrameInfo : public Malloced {
   friend class Deoptimizer;
 };
 
-enum class SpeculationModeChange {
-  kNoSpeculationModeChange = 0,
-  kSetSpeculationDisallow = 1
-};
-
 }  // namespace internal
 }  // namespace v8