Scribble should emit try/require annotations before all other when instrumenting

[cd1m0]

Given this sample:

/// #try foo;
/// #if_succeeds old(bar);
function moo() {
 ....
}

scribble currently emits the code for old(bar) before the code for #try foo. This can sometimes be a problem, when the fuzzer is having trouble getting past some part of bar, and needs the annotation for foo to figure things out.

Instead we should make sure to emit the code for all #try and #require annotations first, to make sure they first help the fuzzer explore the space, before it hits the actual annotation code.

[cd1m0]

Fixed in #274.