Put arm32 backend behind experimental_arm32 flag

cranelift/filetests/filetests/vcode/arm32/aluops.clif

@@ -1,5 +1,6 @@
 test compile
 target arm
+feature "experimental_arm32"
 
 function %iadd(i8, i8) -> i8 {
 block0(v0: i8, v1: i8):

cranelift/filetests/filetests/vcode/arm32/bitops.clif

@@ -1,5 +1,6 @@
 test compile
 target arm
+feature "experimental_arm32"
 
 function %bitrev_i8(i8) -> i8 {
 block0(v0: i8):

cranelift/filetests/filetests/vcode/arm32/cond.clif

@@ -1,5 +1,6 @@
 test compile
 target arm
+feature "experimental_arm32"
 
 function %icmp(i32, i32) -> b1 {
 block0(v0: i32, v1: i32):

cranelift/filetests/filetests/vcode/arm32/constants.clif

@@ -1,5 +1,6 @@
 test compile
 target arm
+feature "experimental_arm32"
 
 function %b1() -> b1 {
 block0:

cranelift/filetests/filetests/vcode/arm32/control-flow.clif

@@ -1,5 +1,6 @@
 test compile
 target arm
+feature "experimental_arm32"
 
 function %brnz(b1) -> i32 {
 block0(v0: b1):

cranelift/filetests/filetests/vcode/arm32/extend.clif

@@ -1,5 +1,6 @@
 test compile
 target arm
+feature "experimental_arm32"
 
 function %uextend_i8_i32(i8) -> i32 {
 block0(v0: i8):

cranelift/filetests/filetests/vcode/arm32/params.clif

@@ -1,5 +1,6 @@
 test compile
 target arm
+feature "experimental_arm32"
 
 function %args(i32) -> i32 {
     sig0 = (i32, i32, i32, i32) -> i32

cranelift/filetests/filetests/vcode/arm32/shift-rotate.clif

@@ -1,5 +1,6 @@
 test compile
 target arm
+feature "experimental_arm32"
 
 function %ishl_i8(i8, i8) -> i8 {
 block0(v0: i8, v1: i8):

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");
     }