Add MODE_MULTI_PROCESS flag to Context.getSharedPreferences()

Also, changes to make this testable with CTS:

-- special PENALTY_DEATH StrictMode fast path that doesn't use
   the Looper idling to "time" the violation.  Only used when
   death is the only violation,

-- make PENALTY_DEATH throw a RuntimeException instead of
   killing its process with a signal.  this means we can catch
   it in CTS tests, but it's also more consistent with
   PENALTY_NETWORK_DEATH in Honeycomb.

-- make FileUtils.getFileStatus() invoke StrictMode, which isn't
   (yet?) aware of I/O in native code.  so help it out.

CTS test for MODE_MULTI_PROCESS is in I6154edab

Change-Id: Icf93f9dfb0ece06b16781e4803dd2c17df3cf1b3