Only run reference types tests on x86_64

Cranelift does not support reference types on other targets.

build.rs

@@ -209,9 +209,12 @@ fn ignore(testsuite: &str, testname: &str, strategy: &str) -> bool {
             // testsuite repo.
             ("simd", "simd_const") => return true,
 
+            // Cranelift only supports reference types on x64.
+            #[cfg(target_arch = "x86_64")]
+            ("reference_types", "table_copy_on_imported_tables")
+            | ("reference_types", "externref_id_function") => return false,
+
             // Still working on implementing these. See #929.
-            ("reference_types", "table_copy_on_imported_tables") => return false,
-            ("reference_types", "externref_id_function") => return false,
             ("reference_types", _) => return true,
 
             _ => {}