winch: Enable memory64 in Winch (#8194)

Closes: #8089

This commit  unlocks support for the `memory64` proposal in Winch. After all the fixes to heap handling, all the spec and misc tests are passing, which is a good indication regarding the support for this proposal.

I'll like to merge this change after: #8156.

build.rs

@@ -241,6 +241,10 @@ fn ignore(testsuite: &str, testname: &str, strategy: &str) -> bool {
             return denylist || ref_types || simd;
         }
 
+        if testsuite == "memory64" {
+            return testname.starts_with("simd") || testname.starts_with("threads");
+        }
+
         if testsuite != "winch" {
             return true;
         }

crates/fuzzing/src/generators/config.rs

@@ -342,7 +342,6 @@ impl Config {
     pub fn disable_unimplemented_winch_proposals(&mut self) {
         self.module_config.config.simd_enabled = false;
         self.module_config.config.relaxed_simd_enabled = false;
-        self.module_config.config.memory64_enabled = false;
         self.module_config.config.gc_enabled = false;
         self.module_config.config.threads_enabled = false;
         self.module_config.config.tail_call_enabled = false;

winch/codegen/src/codegen/env.rs

@@ -328,8 +328,7 @@ impl<'a, 'translation, 'data, P: PtrSize> FuncEnv<'a, 'translation, 'data, P> {
                     current_length_offset,
                     style,
                     ty: if plan.memory.memory64 {
-                        // TODO: Add support for 64-bit memories.
-                        unimplemented!("memory64")
+                        WasmValType::I64
                     } else {
                         WasmValType::I32
                     },