[heap] Remove NewSpace shrinking logic in CollectAllAvailableGarbage.

NewSpace shrinking is already performed in Heap::GarbageCollectionEpilogueInSafepoint.

Bug: chromium:1054771
Change-Id: Ia274dd5619fd1d7397a06f0b642f07d68de45ea1
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2563267
Commit-Queue: Hannes Payer <hpayer@chromium.org>
Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#71451}

src/heap/heap.cc

@@ -1406,10 +1406,6 @@ void Heap::CollectAllAvailableGarbage(GarbageCollectionReason gc_reason) {
   }
 
   set_current_gc_flags(kNoGCFlags);
-  new_space_->Shrink();
-  new_lo_space_->SetCapacity(new_space_->Capacity() *
-                             kNewLargeObjectSpaceToSemiSpaceRatio);
-  UncommitFromSpace();
   EagerlyFreeExternalMemory();
 
   if (FLAG_trace_duplicate_threshold_kb) {

src/heap/new-spaces.cc

@@ -457,7 +457,7 @@ void NewSpace::Shrink() {
   if (rounded_new_capacity < TotalCapacity() &&
       to_space_.ShrinkTo(rounded_new_capacity)) {
     // Only shrink from-space if we managed to shrink to-space.
-    from_space_.Reset();
+    if (from_space_.is_committed()) from_space_.Reset();
     if (!from_space_.ShrinkTo(rounded_new_capacity)) {
       // If we managed to shrink to-space but couldn't shrink from
       // space, attempt to grow to-space again.