am 1642edb5: Merge changes Ib074192d,I6df3afed,I69070455,Icbe31908,Id3fa4526,I038d451f

* commit '1642edb5208fe02ef64d5734fffaf7c4a724fd2f':
  bionic: store property names as variable-length strings
  bionic: prevent root processes from calling __system_property_add
  bionic: revert to a single (larger) property area
  bionic: reimplement property area as hybrid trie/binary tree
  bionic: add missing memory barriers to system properties
  bionic: make property area expandable