[heap] Remove custom Scavenger trace events

Those trace events are too fine grained and heavily impact metrics
computation.

No-try: true
Change-Id: Ica07bfdf8e695689795abb1d6b215c329413ba3b
Reviewed-on: https://chromium-review.googlesource.com/c/1307431
Commit-Queue: Michael Lippautz <mlippautz@chromium.org>
Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#57143}

src/heap/scavenger.cc

@@ -363,7 +363,6 @@ void Scavenger::AddPageToSweeperIfNecessary(MemoryChunk* page) {
 }
 
 void Scavenger::ScavengePage(MemoryChunk* page) {
-  TRACE_EVENT0(TRACE_DISABLED_BY_DEFAULT("v8.gc"), "Scavenger::ScavengePage");
   CodePageMemoryModificationScope memory_modification_scope(page);
   RememberedSet<OLD_TO_NEW>::Iterate(page,
                                      [this](MaybeObjectSlot addr) {
@@ -383,7 +382,6 @@ void Scavenger::ScavengePage(MemoryChunk* page) {
 }
 
 void Scavenger::Process(OneshotBarrier* barrier) {
-  TRACE_EVENT0(TRACE_DISABLED_BY_DEFAULT("v8.gc"), "Scavenger::Process");
   ScavengeVisitor scavenge_visitor(this);
 
   const bool have_barrier = barrier != nullptr;