Closes: bytecodealliance#8096

This commit threads `anyhow::Result`  through most of Winch's
compilation process in order to gracefully handle compilation errors
gracefully instead of panicking.

The error classification is intentionally very granular, to avoid string
allocation which could impact compilation performance.

The errors are largely fit in two categories:

* Unimplemented/Unsupported
* Internal

The firs category signals partial or no support for Wasmtime features
and or Wasm proposals. These errors are meant to be temporary while
such features or proposals are in development.

The second category signals that a compilation invariant was not met.
These errors are considered internal and their presence usually means
a bug in the compiler.

Closes: bytecodealliance#8096

This commit threads `anyhow::Result`  through most of Winch's
compilation process in order to gracefully handle compilation errors
gracefully instead of panicking.

The error classification is intentionally very granular, to avoid string
allocation which could impact compilation performance.

The errors are largely fit in two categories:

* Unimplemented/Unsupported
* Internal

The firs category signals partial or no support for Wasmtime features
and or Wasm proposals. These errors are meant to be temporary while
such features or proposals are in development.

The second category signals that a compilation invariant was not met.
These errors are considered internal and their presence usually means
a bug in the compiler.

* winch: Gracefully handle compilation errors

Closes: #8096

This commit threads `anyhow::Result`  through most of Winch's
compilation process in order to gracefully handle compilation errors
gracefully instead of panicking.

The error classification is intentionally very granular, to avoid string
allocation which could impact compilation performance.

The errors are largely fit in two categories:

* Unimplemented/Unsupported
* Internal

The firs category signals partial or no support for Wasmtime features
and or Wasm proposals. These errors are meant to be temporary while
such features or proposals are in development.

The second category signals that a compilation invariant was not met.
These errors are considered internal and their presence usually means
a bug in the compiler.

* Include `Result` in the MacroAssembler

This commit updates the MacroAssembler trait to require returning
`Result<T>`  on every method in the interface, making it easier to
detect partial support for Masm instructions.