Contribution of PowerPC port (continuation of 422063005, 817143002,
866843003, and 901083004. The bulk of the changes are to remove some
hard coded assumptions about heap page size within existing tests.
The remaining change is to use a larger heap page size for PPC linux
as this provides a performance benefit due to the larger memory page size.

	modified:   src/base/build_config.h
	modified:   src/heap/heap.cc
	modified:   test/cctest/test-alloc.cc
	modified:   test/cctest/test-constantpool.cc
	modified:   test/cctest/test-heap.cc
	modified:   test/cctest/test-spaces.cc
	modified:   test/cctest/test-weakmaps.cc
	modified:   test/cctest/test-weaksets.cc

R=danno@chromium.org, svenpanne@chromium.org

BUG=

Review URL: https://codereview.chromium.org/910333004

Cr-Commit-Position: refs/heads/master@{#26833}