Vulkan: Allow shutdown with init commands.

On startup, when immediately shutting down, there will be init commands
from creating the backbuffers.  Rather than fight this, just free them.

This fixes hangs when locking/unlocking Android.

ext/native/thin3d/VulkanRenderManager.cpp

@@ -225,8 +225,12 @@ void VulkanRenderManager::StopThread() {
 		// when we restart...
 		for (int i = 0; i < vulkan_->GetInflightFrames(); i++) {
 			auto &frameData = frameData_[i];
-			if (frameData.readyForRun || frameData.hasInitCommands || frameData.steps.size() != 0) {
-				Crash();
+			_assert_(!frameData.readyForRun);
+			_assert_(frameData.steps.empty());
+			if (frameData.hasInitCommands) {
+				// Clear 'em out.  This can happen on restart sometimes.
+				vkEndCommandBuffer(frameData.initCmd);
+				frameData.hasInitCommands = false;
 			}
 			frameData.readyForRun = false;
 			for (size_t i = 0; i < frameData.steps.size(); i++) {