Tidy up some internals of instance allocation (#5346)

* Simplify the `ModuleRuntimeInfo` trait slightly

Fold two functions into one as they're only called from one location
anyway.

* Remove ModuleRuntimeInfo::signature

This is redundant as the array mapping is already stored within the
`VMContext` so that can be consulted rather than having a separate trait
function for it. This required altering the `Global` creation slightly
to work correctly in this situation.

* Remove a now-dead constant

* Shared `VMOffsets` across instances

This commit removes the computation of `VMOffsets` to being per-module
instead of per-instance. The `VMOffsets` structure is also quite large
so this shaves off 112 bytes per instance which isn't a huge impact but
should help lower the cost of instantiating small modules.

* Remove `InstanceAllocator::adjust_tunables`

This is no longer needed or necessary with the pooling allocator.

* Fix compile warning

* Fix a vtune warning

* Fix pooling tests

* Fix another test warning

crates/environ/src/vmoffsets.rs

@@ -31,11 +31,6 @@ use cranelift_entity::packed_option::ReservedValue;
 use std::convert::TryFrom;
 use wasmtime_types::OwnedMemoryIndex;
 
-/// Sentinel value indicating that wasm has been interrupted.
-// Note that this has a bit of an odd definition. See the `insert_stack_check`
-// function in `cranelift/codegen/src/isa/x86/abi.rs` for more information
-pub const INTERRUPTED: usize = usize::max_value() - 32 * 1024;
-
 #[cfg(target_pointer_width = "32")]
 fn cast_to_u32(sz: usize) -> u32 {
     u32::try_from(sz).unwrap()