Oilpan: Marking time measurement should not measure the time taken in postGC()

Source/platform/heap/Heap.cpp

Index: Source/platform/heap/Heap.cpp
diff --git a/Source/platform/heap/Heap.cpp b/Source/platform/heap/Heap.cpp
index 0adea02c3daaa03841489548be8fbe938a071c22..db7500b6eab5290571dac931d636219b156ae153 100644
--- a/Source/platform/heap/Heap.cpp
+++ b/Source/platform/heap/Heap.cpp
@@ -2039,8 +2039,6 @@ void Heap::collectGarbage(ThreadState::StackState stackState, ThreadState::GCTyp
     // we should have crashed during marking before getting here.)
     orphanedPagePool()->decommitOrphanedPages();
 
-    postGC(gcType);
-
     double markingTimeInMilliseconds = WTF::currentTimeMS() - timeStamp;
     s_estimatedMarkingTimePerByte = totalObjectSize ? (markingTimeInMilliseconds / 1000 / totalObjectSize) : 0;
 
@@ -2051,6 +2049,8 @@ void Heap::collectGarbage(ThreadState::StackState stackState, ThreadState::GCTyp
     Heap::reportMemoryUsageHistogram();
     WTF::Partitions::reportMemoryUsageHistogram();
 
+    postGC(gcType);
+
     if (state->isMainThread())
         ScriptForbiddenScope::exit();
 }