perf(turbopack): Box ConstantValue::Regex (#74968)

### What?

Box the `Regex` variant of `ConstantValue`

### Why?

Data-oriented Design!

This variant is not created frequently compared to other variants, so we can box it to reduce the size of the type.

turbopack/crates/turbopack-ecmascript/src/analyzer/mod.rs

@@ -170,7 +170,7 @@ pub enum ConstantValue {
     False,
     Null,
     BigInt(Box<BigInt>),
-    Regex(Atom, Atom),
+    Regex(Box<(Atom, Atom)>),
 }
 
 impl ConstantValue {
@@ -252,7 +252,7 @@ impl From<Lit> for ConstantValue {
             Lit::Null(_) => ConstantValue::Null,
             Lit::Num(v) => ConstantValue::Num(ConstantNumber(v.value)),
             Lit::BigInt(v) => ConstantValue::BigInt(v.value),
-            Lit::Regex(v) => ConstantValue::Regex(v.exp, v.flags),
+            Lit::Regex(v) => ConstantValue::Regex(Box::new((v.exp, v.flags))),
             Lit::JSXText(v) => ConstantValue::Str(ConstantString::Atom(v.value)),
         }
     }
@@ -268,7 +268,7 @@ impl Display for ConstantValue {
             ConstantValue::Null => write!(f, "null"),
             ConstantValue::Num(ConstantNumber(n)) => write!(f, "{n}"),
             ConstantValue::BigInt(n) => write!(f, "{n}"),
-            ConstantValue::Regex(exp, flags) => write!(f, "/{exp}/{flags}"),
+            ConstantValue::Regex(regex) => write!(f, "/{}/{}", regex.0, regex.1),
         }
     }
 }
@@ -3732,7 +3732,7 @@ pub fn parse_require_context(args: &[JsValue]) -> Result<RequireContextOptions>
     };
 
     let filter = if let Some(filter) = args.get(2) {
-        if let JsValue::Constant(ConstantValue::Regex(pattern, flags)) = filter {
+        if let JsValue::Constant(ConstantValue::Regex(box (pattern, flags))) = filter {
             regex_from_js(pattern, flags)?
         } else {
             bail!("require.context(..., ..., filter) requires filter to be a regex");

turbopack/crates/turbopack-ecmascript/src/utils.rs

@@ -32,7 +32,7 @@ pub fn js_value_to_pattern(value: &JsValue) -> Pattern {
             ConstantValue::Null => "null".into(),
             ConstantValue::Num(ConstantNumber(n)) => n.to_string().into(),
             ConstantValue::BigInt(n) => n.to_string().into(),
-            ConstantValue::Regex(exp, flags) => format!("/{exp}/{flags}").into(),
+            ConstantValue::Regex(box (exp, flags)) => format!("/{exp}/{flags}").into(),
             ConstantValue::Undefined => "undefined".into(),
         }),
         JsValue::Url(v, JsValueUrlKind::Relative) => Pattern::Constant(v.as_str().into()),

turbopack/crates/turbopack-ecmascript/tests/analyzer/graph/require-context/graph-effects.snapshot

@@ -127,8 +127,10 @@
             Value(
                 Constant(
                     Regex(
-                        "\\.test\\.js$",
-                        "",
+                        (
+                            "\\.test\\.js$",
+                            "",
+                        ),
                     ),
                 ),
             ),

turbopack/crates/turbopack-ecmascript/tests/analyzer/graph/require-context/graph.snapshot

@@ -54,8 +54,10 @@
                 ),
                 Constant(
                     Regex(
-                        "\\.test\\.js$",
-                        "",
+                        (
+                            "\\.test\\.js$",
+                            "",
+                        ),
                     ),
                 ),
             ],