ConvertConstructorCallIntoInitializer needs dedicated pretty test

[siegfriedpammer]

While working on #1378, I discovered that there are some special cases with .cctor and beforefieldinit. We currently do not have dedicated tests that enumerate all possible ways of initializing fields.

[siegfriedpammer]

One problem:

public class Test
{
	public static int a = 4;
	static Test()
	{
	}
}

gets decompiled as:

public class Test
{
	public static int a;
	static Test()
	{
		a = 4;
	}
}

The problem is, as soon as there is a static ctor defined in a type, the beforefieldinit flag no longer is emitted. The current transform does not transform type initializers that do not have the flag set on their type.