This commit is a fairly large refactor, mainly because it unified the
two different ways that existed to represent references.
Now Reference values are also a kind of value.
It also implements a printer for values/references instead of copying
the implementation everywhere.
Managing the instantiated modules becomes a pain if they're on the
stack, since an instantiated module will eventually reference itself.
To make using this simpler, just avoid copying the instance.
This fixes a FIXME and will allow linking only select modules together,
instead of linking every instantiated module into a big mess of exported
entities :P
This also optionally generates a test suite from the WebAssembly
testsuite, which can be enabled via passing `INCLUDE_WASM_SPEC_TESTS`
to cmake, which will generate test-wasm-compatible tests and the
required fixtures.
The generated directories are excluded from git since there's no point
in committing them.
This only tests "can it be parsed", but the goal of this commit is to
provide a test framework that can be built upon :)
The conformance tests are downloaded, compiled* and installed only if
the INCLUDE_WASM_SPEC_TESTS cmake option is enabled.
(*) Since we do not yet have a wast parser, the compilation is delegated
to an external tool from binaryen, `wasm-as`, which is required for the
test suite download/install to succeed.
This *does* run the tests in CI, but it currently does not include the
spec conformance tests.
