implement fuzzing for component types (#4537)

This addresses #4307.

For the static API we generate 100 arbitrary test cases at build time, each of
which includes 0-5 parameter types, a result type, and a WAT fragment containing
an imported function and an exported function.  The exported function calls the
imported function, which is implemented by the host.  At runtime, the fuzz test
selects a test case at random and feeds it zero or more sets of arbitrary
parameters and results, checking that values which flow host-to-guest and
guest-to-host make the transition unchanged.

The fuzz test for the dynamic API follows a similar pattern, the only difference
being that test cases are generated at runtime.

Signed-off-by: Joel Dice <joel.dice@fermyon.com>

crates/component-macro/src/lib.rs

@@ -885,7 +885,10 @@ impl Expander for ComponentTypeExpander {
                 const SIZE32: usize = {
                     let mut size = 0;
                     #sizes
-                    #internal::align_to(#discriminant_size as usize, Self::ALIGN32) + size
+                    #internal::align_to(
+                        #internal::align_to(#discriminant_size as usize, Self::ALIGN32) + size,
+                        Self::ALIGN32
+                    )
                 };
 
                 const ALIGN32: u32 = {