[heap] Fix comment for Page in spaces.h

Change-Id: Ib95ab0c5669fe344ff199cc6cad811e175bc8bb3
Reviewed-on: https://chromium-review.googlesource.com/565410Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Commit-Queue: Albert Mingkun Yang <albertnetymk@google.com>
Cr-Commit-Position: refs/heads/master@{#46520}

src/heap/spaces.h

@@ -736,7 +736,7 @@ inline intptr_t MarkingState::live_bytes<AccessMode::ATOMIC>() const {
 }
 
 // -----------------------------------------------------------------------------
-// A page is a memory chunk of a size 1MB. Large object pages may be larger.
+// A page is a memory chunk of a size 512K. Large object pages may be larger.
 //
 // The only way to get a page pointer is by calling factory methods:
 //   Page* p = Page::FromAddress(addr); or