PPC64: Changing test-spaces/SizeOfInitialHeap to accomodate 64K page size

    Since the page size of PPC 64 bit machines is 64K, memory smaller than 64K
    cannot be freed causing the committed memory of code space to be
    exactly 2M. Changing the test case to accomodate this.

R=mlippautz@chromium.org, ulan@chromium.org, vogelheim@chromium.org
BUG=

Review-Url: https://codereview.chromium.org/2523293002
Cr-Commit-Position: refs/heads/master@{#41292}

test/cctest/heap/test-spaces.cc

@@ -503,9 +503,15 @@ TEST(SizeOfInitialHeap) {
   // Initial size of LO_SPACE
   size_t initial_lo_space = isolate->heap()->lo_space()->Size();
 
-  // The limit for each space for an empty isolate containing just the
-  // snapshot.
+// The limit for each space for an empty isolate containing just the
+// snapshot.
+// In PPC the page size is 64K, causing more internal fragmentation
+// hence requiring a larger limit.
+#if V8_OS_LINUX && V8_HOST_ARCH_PPC
+  const size_t kMaxInitialSizePerSpace = 3 * MB;
+#else
   const size_t kMaxInitialSizePerSpace = 2 * MB;
+#endif
 
   // Freshly initialized VM gets by with the snapshot size (which is below
   // kMaxInitialSizePerSpace per space).