test: make tests work on more targets

[explodingcamera]

• Tests can now be run on more targets (Fixes Tests fail to compile on armv7 (Raspberry Pi 4) #7)
• Nightly version has been updated to fix broken builds in some cases (Fixes Tests fail to compile on aarch64 (Apple M1 Max) #8)

[drauschenbach]

FYI, still having trouble invoking tests on Rpi4 armv7.

$ cargo test
...
   Compiling wat v1.0.71
   Compiling tinywasm-root v0.0.0 (/home/davidr/workspace/tinywasm)
error: couldn't read examples/./rust/out/tinywasm.wasm: No such file or directory (os error 2)
  --> examples/wasm-rust.rs:57:29
   |
57 |     const TINYWASM: &[u8] = include_bytes!("./rust/out/tinywasm.wasm");
   |                             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   |
   = note: this error originates in the macro `include_bytes` (in Nightly builds, run with -Z macro-backtrace for more info)

error: couldn't read examples/./rust/out/hello.wasm: No such file or directory (os error 2)
  --> examples/wasm-rust.rs:79:31
   |
79 |     const HELLO_WASM: &[u8] = include_bytes!("./rust/out/hello.wasm");
   |                               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   |
   = note: this error originates in the macro `include_bytes` (in Nightly builds, run with -Z macro-backtrace for more info)

error: couldn't read examples/./rust/out/print.wasm: No such file or directory (os error 2)
   --> examples/wasm-rust.rs:109:31
    |
109 |     const HELLO_WASM: &[u8] = include_bytes!("./rust/out/print.wasm");
    |                               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
    = note: this error originates in the macro `include_bytes` (in Nightly builds, run with -Z macro-backtrace for more info)

error: couldn't read examples/./rust/out/fibonacci.wasm: No such file or directory (os error 2)
   --> examples/wasm-rust.rs:131:35
    |
131 |     const FIBONACCI_WASM: &[u8] = include_bytes!("./rust/out/fibonacci.wasm");
    |                                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
    = note: this error originates in the macro `include_bytes` (in Nightly builds, run with -Z macro-backtrace for more info)

error: could not compile `tinywasm-root` (example "wasm-rust") due to 4 previous errors
warning: build failed, waiting for other jobs to finish...

[explodingcamera]

@drauschenbach
It's a bit unfortunate that cargo still compiles these even though that example is marked as test=false, so I've now just changed it to read the Wasm dynamically, so tests still pass without those files (8477bff).

There's an explanation on what's required for these examples to run at the top of the file:

tinywasm/examples/wasm-rust.rs

Lines 4 to 19 in 0302008

	/// Examples of using WebAssembly compiled from Rust with tinywasm.
	///
	/// These examples are meant to be run with `cargo run --example wasm-rust <example>`.
	/// For example, `cargo run --example wasm-rust hello`.
	///
	/// To run these, you first need to compile the Rust examples to WebAssembly:
	///
	/// ```sh
	/// ./examples/rust/build.sh
	/// ```
	///
	/// This requires the `wasm32-unknown-unknown` target, `binaryen` and `wabt` to be installed.
	/// `rustup target add wasm32-unknown-unknown`.
	/// https://github.com/WebAssembly/wabt
	/// https://github.com/WebAssembly/binaryen
	///

[drauschenbach]

It's fixed now.