Only run reference types tests on x86_64

Cranelift does not support reference types on other targets.

build.rs

@@ -209,9 +209,14 @@ fn ignore(testsuite: &str, testname: &str, strategy: &str) -> bool {
             // testsuite repo.
             ("simd", "simd_const") => return true,
 
+            ("reference_types", "table_copy_on_imported_tables")
+            | ("reference_types", "externref_id_function") => {
+                // Ignore if this isn't x64, because Cranelift only supports
+                // reference types on x64.
+                return env::var("CARGO_CFG_TARGET_ARCH").unwrap() != "x86_64";
+            }
+
             // 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,
 
             _ => {}

tests/all/main.rs

@@ -4,7 +4,6 @@ mod debug;
 mod externals;
 mod func;
 mod fuzzing;
-mod gc;
 mod globals;
 mod iloop;
 mod import_calling_export;
@@ -19,3 +18,7 @@ mod table;
 mod traps;
 mod use_after_drop;
 mod wast;
+
+// Cranelift only supports reference types on x64.
+#[cfg(target_arch = "x86_64")]
+mod gc;