Also:
- make sure to apply diversions when determining offsets for code
relaxation.
- select the smallest encoding when selecting a relaxed branch
instruction.
- Both the `wasm` and `compile` commands get this new subcommand, and it defaults to false. This means that test runs with `wasm` can request disassembly (the main reason I am doing this) while test runs with `compile` now must request it, this changes current behavior.
- Switch to using context.compile_and_emit directly, and make the reloc and trap printers just accumulate output, not print it. This allows us to factor the printing code into the disasm module.
* Use single index for param register allocation for windows callconv (#691)
The used registers depend entirely on the parameter index (1st, 2nd, 3rd, 4th, ... param)
and we cannot shift unused registers to other indexes, if they are not designated for
the use for that parameter index.
This was previously using the following condition to decide that a block
hadn't been visited yet: either dest_offset is non-0 or the block isn't
the entry block. Unfortunately, this didn't work when the first block
would be non-empty but wouldn't generate code at all.
Since the original code would do at least one pass over the entire code,
the first pass that determines initial EBB offsets is done separately,
without considering branch relaxation. This ensures that all EBBs have
been visited and have correct initial offsets, and doesn't require a
special check to know whether an EBB has been visited or not.
