Match the Go runtime by terminating for deadlocks, stack overflows,
runtime and GC invariants, invalid lock operations, and platform
initialization failures instead of routing them through panic/recover.
Keep language-level runtime errors and unsupported user operations
recoverable. Add crash coverage that verifies fatal errors bypass deferred
recover calls.
- Do not use make([]byte, ...) to allocate, instead call the allocator
directly with a nil (undefined) layout. This makes sure the precise
GC will scan the contents of the allocation, since C could very well
put pointers in there.
- Simplify the map to use the pointer as the key and the size as the
value, instead of storing the slices directly in the map.
This adds support for `-gc=boehm` on `-target=wasip1` and `-target=wasm`
(in a browser or NodeJS). Notably it does *not* add Boehm GC support for
`-target=wasip2`, since that target doesn't have a real libc.