PPC: fix allocation issues for PPC64.

test/cctest/test-strings.cc

Index: test/cctest/test-strings.cc
diff --git a/test/cctest/test-strings.cc b/test/cctest/test-strings.cc
index 9a4e96ffd5cc1c9c06f4bbb30387fa66c7522906..8d5129cd05e50b42338f4079f585c677f9f73bd4 100644
--- a/test/cctest/test-strings.cc
+++ b/test/cctest/test-strings.cc
@@ -1209,7 +1209,7 @@ UNINITIALIZED_TEST(OneByteArrayJoin) {
   v8::Isolate::CreateParams create_params;
   // Set heap limits.
   create_params.constraints.set_max_semi_space_size(1);
-  create_params.constraints.set_max_old_space_size(5);
+  create_params.constraints.set_max_old_space_size(6);
   v8::Isolate* isolate = v8::Isolate::New(create_params);
   isolate->Enter();