[analyzer] @:pure meta lost in CFG building

If we have the following:
```haxe
class Main {
@:pure inline static function f() trace("hi");

@:analyzer(full_debug)
static function main() {
f();
}
}
```

The inlined call to `f()` is not being eliminated even though it's `@:pure`, because the `TMeta` is lost when building control flow graph basic blocks:

```
While analyzing Main.main

function() {
@:pure `trace<535>("hi", {fileName : "Main.hx", lineNumber : 2, className : "Main", methodName : "f"});
}

function() {
@:pure `trace<535>("hi", {fileName : "Main.hx", lineNumber : 2, className : "Main", methodName : "f"});
}

function() {
`trace<535>("hi", {fileName : "Main.hx", lineNumber : 2, className : "Main", methodName : "f"});
}

function() {
`trace<535>("hi", {fileName : "Main.hx", lineNumber : 2, className : "Main", methodName : "f"});
}

function() {
`trace<535>("hi", {fileName : "Main.hx", lineNumber : 2, className : "Main", methodName : "f"});
}

```