Prevent WakeLock count ending up in an incorrect state

WakeLock can end up in a bad state if the following sequence
is executed:

1. mWakeLock =  mPowerManager.newWakeLock(...)
2. mWakeLock.acquire(TIMEOUT_MS);
3. timeout TIMEOUT_MS occurs before release() is called
4. release is called()

[1] mInternalCount = mExternalCount = 0
[2] mInternalCount = 1, mExternalCount = 1
[3] mInternalCount = 0, mExternalCount = 1
[4] mInternalCount = -1, mExternalCount = 0

If acquireLocked is called on the same object after this sequence,
mInternalCount is incremented to 0 which results in no wakelock
being requested from PowerManagerService.

Bug: 64676694
Test: cts-tradefed run commandAndExit cts-dev -m CtsOsTestCases -t android.os.cts.PowerManager_WakeLockTest
Change-Id: I133812aefb5d92eec2e2dde1a36f81dc9ffd7625

core/java/android/os/PowerManager.java

@@ -1412,7 +1412,11 @@ public final class PowerManager {
          */
         public void release(int flags) {
             synchronized (mToken) {
-                mInternalCount--;
+                if (mInternalCount > 0) {
+                    // internal count must only be decreased if it is > 0 or state of
+                    // the WakeLock object is broken.
+                    mInternalCount--;
+                }
                 if ((flags & RELEASE_FLAG_TIMEOUT) == 0) {
                     mExternalCount--;
                 }