Revert "Enforce that a PendingIntent has an explicit mutability ..."

Revert "PendingIntentTest: Add tests to check enforced mutabilit..."

Revert submission 13048968-pi-enforce-mutability-flag

Reason for revert: Lots of regressions since merging this, reverting to address those.
Reverted Changes:
If49be6141:Enforce that a PendingIntent has an explicit mutab...
I885d1b558:PendingIntentTest: Add tests to check enforced mut...

Change-Id: I371cef3b423c23736b520ca5c29ee4ff9c51bb33
diff --git a/core/java/android/app/PendingIntent.java b/core/java/android/app/PendingIntent.java
index b8b9d9f..9dbf1ff6 100644
--- a/core/java/android/app/PendingIntent.java
+++ b/core/java/android/app/PendingIntent.java
@@ -352,9 +352,7 @@
 
         if (Compatibility.isChangeEnabled(PENDING_INTENT_EXPLICIT_MUTABILITY_REQUIRED)
                 && !flagImmutableSet && !flagMutableSet) {
-            Log.wtf(TAG, msg);
-            throw new IllegalArgumentException(
-                "Please specify an explicit mutability flag (FLAG_IMMUTABLE or FLAG_MUTABLE)");
+            Log.e(TAG, msg);
         }
     }