Fix a bug: unable to start activity when AM is killing the process.

Symptom: No activity was started for startActivity, low repro rate.
Root Cause: Starting activity on a process which was killed by ActivityManagerService.killUnneededProcessLocked() and before receiving AppDeathRecipient of it.
Solution: Choose the flow of starting a new process if ProcessRecord.killedByAm is true.

Change-Id: Ida2639b0fb4631222fc92d65aadc9fd2da637b45
Text size for empty view shall be styled according to theme

In activity_list.xml the empty TextView has set a
textAppearance which allows the theme to set the font size.
However, for preference_list_fragment.xml the textAppearance
is missing but should follow the same style as
activity_list.xml

The missing textAppearance makes the empty text in
Settings->Wifi and Settings->Bluetooth look small if
no networks are found.

Change-Id: I9320b37cfeec0d9505d73650696eaf534fc4a321