Revert^2 "ART: add GC time ratio metrics to GC performance"

Make GC time ratio metrics work for all collectors.

This reverts commit 4d57c69ab7753690738d9dc802b5b640cb6af491.

Test: Run art with -XX:DumpGCPerformanceOnShutdown on some benchmarks.
Bug: 112187497
Change-Id: I5cce0cf2a5204126b70b7c8fdf686986f9b3d7e7
diff --git a/runtime/gc/heap.cc b/runtime/gc/heap.cc
index f0f81fc..e7f14c3 100644
--- a/runtime/gc/heap.cc
+++ b/runtime/gc/heap.cc
@@ -1062,6 +1062,14 @@
   }
 }
 
+uint64_t Heap::GetTotalGcCpuTime() {
+  uint64_t sum = 0;
+  for (auto& collector : garbage_collectors_) {
+    sum += collector->GetTotalCpuTime();
+  }
+  return sum;
+}
+
 void Heap::DumpGcPerformanceInfo(std::ostream& os) {
   // Dump cumulative timings.
   os << "Dumping cumulative Gc timings\n";