This reverts commit 1946856b1f18a27c51ba30bb9e304f25b722ee05.
This goes back to the original scheme of PROT_NONEing a page within
libc. Allocating a new page didn't fail safe for cases where these
functions are called from the dynamic linker.
Bug: http://b/22568628
Change-Id: I3e7241c8b54c27ea4a898bc952375c1e9ae38c80