Good News: Almost all druntime supported on arsd webassembly

[Hipreme]

Hello people. I have tried working again with adam's wasm minimal 
runtime, and yesterday I was able to make a great progress on it.

Currently, the only feature that I did not bother to implement 
support for was the try/catch/finally/throw friends. Pretty much 
only because I don't use in my engine. I would like to ask you 
guys some feedback on its current usage, I have written a file 
with only tests to the wasm runtime:

```d
// ldc2 -i=. --d-version=CarelessAlocation -i=std 
-Iarsd-webassembly/ -L-allow-undefined -ofserver/omg.wasm 
-mtriple=wasm32-unknown-unknown-wasm 
arsd-webassembly/core/arsd/aa 
arsd-webassembly/core/arsd/objectutils 
arsd-webassembly/core/internal/utf 
arsd-webassembly/core/arsd/utf_decoding hello 
arsd-webassembly/object.d

import arsd.webassembly;
import std.stdio;

class A {
	int _b = 200;
	int a() { return 123; }
}

interface C {
	void test();
}
interface D {
	void check();
}

class B : A, C
{
	int val;
	override int a() { return 455 + val; }

	void test()
	{
		rawlog(a());
		int[] a;
		a~= 1;
	}
}

void rawlog(Args...)(Args a, string file = __FILE__, size_t line 
= __LINE__)
{
	writeln(a, " at "~ file~ ":", line);
}


struct Tester
{
	int b = 50;
	string a = "hello";
}
void main()
{
	float[] f = new float[4];
	assert(f[0] is float.init);
	f~= 5.5; //Append
	f~= [3, 4];
	int[] inlineConcatTest = [1, 2] ~ [3, 4];

	auto dg = delegate()
	{
		writeln(inlineConcatTest[0], f[1]);
	};
	dg();
	B b = new B;
	b.val = 5;
	A a = b;
	a.a();
	C c = b;
	c.test();
	assert(cast(D)c is null);
	Tester[] t = new Tester[10];
	assert(t[0] == Tester.init);
	assert(t.length == 10);

	switch("hello")
	{
		case "test":
			writeln("broken");
			break;
		case "hello":
			writeln("Working switch string");
			break;
		default: writeln("What happenned here?");
	}
	string strTest = "test"[0..$];
	assert(strTest == "test");

	
	Tester* structObj = new Tester(50_000, "Inline Allocation");
	writeln(structObj is null, structObj.a, structObj.b);

	int[string] hello = ["hello": 500];
	assert(("hello" in hello) !is null, "No key hello yet...");
	assert(hello["hello"] == 500, "Not 500");
	hello["hello"] = 1200;
	assert(hello["hello"] == 1200, "Reassign didn't work");
	hello["h2o"] = 250;
	assert(hello["h2o"] == 250, "New member");


	int[] appendTest;
	appendTest~= 50;
	appendTest~= 500;
	appendTest~= 5000;
	foreach(v; appendTest)
		writeln(v);
	string strConcatTest;
	strConcatTest~= "Hello";
	strConcatTest~= "World";
	writeln(strConcatTest);
	int[] intConcatTest = cast(int[2])[1, 2];
	intConcatTest~= 50;
	string decInput = "a";
	decInput~= "こんいちは";
	foreach(dchar ch; "こんいちは")
	{
		decInput~= ch;
		writeln(ch);
	}
	writeln(decInput);
	int[] arrCastTest = [int.max];

	foreach(v; cast(ubyte[])arrCastTest)
		writeln(v);

}
```

All those tests are currently passing. That means we almost got 
all the common features from the D Runtime into Arsd custom 
runtime. Meaning that the only thing that would be missing right 
now being the WASI libc. But my engine is not going to use it 
entirely, only a subset of it. So, I would like to say that 
whoever wants to play with it now is able to do it so.


That being said, I would carefully advice that while I bring 
those implementations, I didn't care about memory leaks, so, it 
is a runtime without GC: careless allocations. But! It is 
possible to port some programs specially if you're already doing 
house clearing yourself. As my engine does not leak memory in 
loop (as that would make it trigger the GC and thus make it 
slow), it is totally possible to use it.

"But why didn't you continued Skoppe's WASM work?", I literally 
am not able to build LDC runtime no matter how hard I tried. 
Doing that work on a minimal runtime was a lot easier.

If you do find any use in the work I've done, please do test it 
as I'll benefit from both you guys test. If you find any 
performance improvement on it, it'll be gladly be accepted.

I do not intend to replace the druntime with that. I've done the 
minimal subset of features that makes my engine work for the web. 
A real druntime is still expected and awaited by me.

The link to the PR to be tested can be found there: 
https://github.com/adamdruppe/webassembly/pull/9