Headers update from bionic for x86_64 support

* Add i386/elf_machdep.h, it is used during the build of 32-bit part of
multilib compiler;
* Remove page.h. See https://android-review.googlesource.com/#/c/83299;
* Update other x86 headers from bionic for compatibility which are
required for successful build;

Change-Id: Ia66301849e699b79c657146424a806d0aa22342b
Signed-off-by: Pavel Chupin <pavel.v.chupin@intel.com>
Merge "Headers update from bionic for x86_64 support"
auto-merger: merge in from aosp/master