[heap] Do not require kRingBufferMaxSize samples for estimating compaction speed

src/heap/gc-tracer.cc

Index: src/heap/gc-tracer.cc
diff --git a/src/heap/gc-tracer.cc b/src/heap/gc-tracer.cc
index 22277c2c363d9f379272614b59a0ed9184adafd2..416ed092b67d3d71a7ca65a74661bc798338ae2a 100644
--- a/src/heap/gc-tracer.cc
+++ b/src/heap/gc-tracer.cc
@@ -731,7 +731,7 @@ intptr_t GCTracer::ScavengeSpeedInBytesPerMillisecond(
 
 
 intptr_t GCTracer::CompactionSpeedInBytesPerMillisecond() const {
-  if (compaction_events_.size() < kRingBufferMaxSize) return 0;
+  if (compaction_events_.size() == 0) return 0;
   intptr_t bytes = 0;
   double durations = 0.0;
   CompactionEventBuffer::const_iterator iter = compaction_events_.begin();