[Android] Replace custom StackLock with platform lock

[austinh0]

Problem

After #9884, Android is using the platform event loop in GenericPlatformManagerImpl_POSIX, which uses the platform lock. However, Android is still using its own custom lock, which results in deadlocks.

Change overview

• Switch to using platform lock:
  • Remove Android-only StackLock.h and custom JniReferences::GetInstance().GetStackLock().
  • Replace StackLockGuard with chip::DeviceLayer::StackLock, and StackUnlockGuard with newly created chip::DeviceLayer::StackUnlock

Testing

• Commissioned and controlled device using Android CHIPTool.

[msandstedt]

PR breaks POSX::_InitChipStack such that reinitialization of chip stack does not initialize the stack lock.

[austinh0]

@bzbarsky-apple @chrisdecenzo @Damian-Nordic @jmartinez-silabs @saurabhst?