Refactor profile sampling

[Looooong]

I find out the weird behaviour of profiler sampling using CommandBuffer (Unity 2018):

CommandBuffer command = new CommandBuffer { name = "Command Name" };
ScriptableRenderContext context;

// Works
command.BeginSample("Something");
command.EndSample("Something");
context.ExecuteCommandBuffer(command);

// Fails
command.BeginSample("Something");
context.ExecuteCommandBuffer(command);
command.Clear();
command.EndSample("Something");
context.ExecuteCommandBuffer(command);

// Works
command.BeginSample(command.name);
context.ExecuteCommandBuffer(command);
command.Clear();
command.EndSample(command.name);
context.ExecuteCommandBuffer(command);