bionic: revert to a single (larger) property area

bionic: revert to a single (larger) property area

d329697 is too complicated.  Change the multiple property pages back to
a single 128K property area that's mapped in entirely at initialization
(the memory will not get allocated until the pages are touched).

d329697 has other changes useful for testing (moving property area
initialization inside bionic and adding __system_property_set_filename)
so undo the change manually rather than with git revert.

Change-Id: Icd137669a4f8bc248e9dd2c1e8cc54e9193c9a6d
Signed-off-by: Greg Hackmann <ghackmann@google.com>