Log various information about non-foreground activity starts

Logging activity starts to TRON, but only if the caller app
doesn't have any foreground activity present.

Example event:
08-03 15:21:30.813  1231  3220 I sysui_multi_action: [757,1513,758,4,805,1533306090812,1514,10147,1515,com.google.android.talk,1516,1018,1517,0,1518,1000,1519,1000,1520,0,1521,10147,1522,com.google.android.talk,1523,1018,1524,0,1525,pendingintent:u0a12:com.google.android.talk/com.google.android.apps.hangouts.phone.ConversationActivity,1526,com.google.android.talk/com.google.android.apps.hangouts.phone.BabelHomeActivity,1527,1,1528,com.google.android.apps.hangouts.phone.conversationlist,1540,1,1541,com.google.android.apps.hangouts.phone.BabelHomeActivity,1542,3146240,1543,{com.google.android.talk/com.google.android.apps.hangouts.phone.BabelHomeActivity},1544,com.google.android.talk/com.google.android.apps.hangouts.phone.BabelHomeActivity,1545,com.google.android.talk,1546,1,1547,0,1551,0,1552,0]

Bug: b/111866309
Context: go/activity-starts-logging-tron
Test: 1) enable logging with: adb shell settings put global activity_starts_logging_enabled 1
      2) open some activities and observe: adb logcat -b events | grep "sysui_multi_action: \[757,1513"
Test: atest FrameworksServicesTests:ActivityStarterTests
Change-Id: Id63806a2d08a50f404268194a05c6e94bd7e9724