Fix issue #62196301: Pre-O background restrictions allow starts...

...from background apps

The check for whether a calling app was in the foreground was
way too lose, treating anything better than a receive as foreground.
Now we use the same foreground state check as elsewhere.

Test: manual

Change-Id: I6bb621f207204d14abfadc0d425297e7d5efe0f6

services/core/java/com/android/server/am/ActivityManagerService.java

@@ -8447,8 +8447,8 @@ public class ActivityManagerService extends IActivityManager.Stub
                         synchronized (mPidsSelfLocked) {
                             proc = mPidsSelfLocked.get(callingPid);
                         }
-                        if (proc != null && proc.curProcState
-                                < ActivityManager.PROCESS_STATE_RECEIVER) {
+                        if (proc != null &&
+                                !ActivityManager.isProcStateBackground(proc.curProcState)) {
                             // Whoever is instigating this is in the foreground, so we will allow it
                             // to go through.
                             return ActivityManager.APP_START_MODE_NORMAL;