Fix issue 381905: BassBoostTest CTS tests fail...

When AudioEffectTest is executed, an Equalizer is created
and enabled on a MediaPlayer session. Effects on the output
mix are therefore suspended.
Then the MediaPlayer is released with the effect still enabled.
In this case, Audioflinger::purgeStaleEffects_l() fails to restore
the suspended effects when the effect attached to the released audio session
is removed.
When subsequent tests are executed on output mix effects, these effects cannot be
enabled as they are still suspended.

Fixed purgeStaleEffects_l() to restore suspended effects if the effect removed is enabled.

Also fixed EffectHandle::disconnect() to only restore suspended effects if the disconnected
handle actually has control over the effect.

Change-Id: I67232e7c34680b0cc01abfd57d5d510a524e5d4f