Reland "[heap] Reduce page size to 256KB"

This is a reland of 8f1c985c

Original change's description:
> [heap] Reduce page size to 256KB
> 
> The page size of PPC is kept unchanged because PPC has larger
> physical pages (64KB).
> 
> Bug: chromium:852420
> 
> Change-Id: Ib888ea00a476ff103e00211dbb439186148ef81e
> Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1481631
> Commit-Queue: Ulan Degenbaev <ulan@chromium.org>
> Reviewed-by: Hannes Payer <hpayer@chromium.org>
> Reviewed-by: Junliang Yan <jyan@ca.ibm.com>
> Cr-Commit-Position: refs/heads/master@{#60296}

Bug: chromium:852420
Change-Id: Id0fbe4759f6fa750bc00100ca521453317dff9ff
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1529006
Auto-Submit: Ulan Degenbaev <ulan@chromium.org>
Reviewed-by: Hannes Payer <hpayer@chromium.org>
Commit-Queue: Hannes Payer <hpayer@chromium.org>
Cr-Commit-Position: refs/heads/master@{#60329}

src/base/build_config.h

@@ -201,8 +201,12 @@
 #define V8_TARGET_ARCH_STORES_RETURN_ADDRESS_ON_STACK false
 #endif
 
-// Number of bits to represent the page size for paged spaces. The value of 19
-// gives 512Kb bytes per page.
+// Number of bits to represent the page size for paged spaces.
+#if defined(V8_TARGET_ARCH_PPC) || defined(V8_TARGET_ARCH_PPC64)
+// PPC has large (64KB) physical pages.
 const int kPageSizeBits = 19;
+#else
+const int kPageSizeBits = 18;
+#endif
 
 #endif  // V8_BASE_BUILD_CONFIG_H_

src/heap/spaces.h

@@ -1948,7 +1948,7 @@ class V8_EXPORT_PRIVATE FreeList {
   static const size_t kTinyListMax = 0x1f * kTaggedSize;
   static const size_t kSmallListMax = 0xff * kTaggedSize;
   static const size_t kMediumListMax = 0x7ff * kTaggedSize;
-  static const size_t kLargeListMax = 0x2fff * kTaggedSize;
+  static const size_t kLargeListMax = 0x1fff * kTaggedSize;
   static const size_t kTinyAllocationMax = kTiniestListMax;
   static const size_t kSmallAllocationMax = kTinyListMax;
   static const size_t kMediumAllocationMax = kSmallListMax;