Put arm32 backend behind experimental_arm32 flag

cranelift/filetests/src/runone.rs

@@ -9,7 +9,7 @@ use cranelift_codegen::print_errors::pretty_verifier_error;
 use cranelift_codegen::settings::Flags;
 use cranelift_codegen::timing;
 use cranelift_codegen::verify_function;
-use cranelift_reader::{parse_test, IsaSpec, ParseOptions};
+use cranelift_reader::{parse_test, Feature, IsaSpec, ParseOptions};
 use log::info;
 use std::borrow::Cow;
 use std::fs;
@@ -51,6 +51,15 @@ pub fn run(
         }
     };
 
+    #[cfg(not(feature = "experimental_arm32"))]
+    if testfile
+        .features
+        .contains(&Feature::With("experimental_arm32"))
+    {
+        println!("skipped {:?}: no experimental_arm32 feature", path);
+        return Ok(started.elapsed());
+    }
+
     if testfile.functions.is_empty() {
         anyhow::bail!("no functions found");
     }