[mono][interp] Fix some leaks during compilation (dotnet#97143)

* [mono][interp] Stop trying to inflate signature

The target method and, implicitly, its signature are already inflated. This was allocating a new signature every time the method was called which was leaked. On some of the bigger tests suites, that heavily use generics, this can reduce the mem usage in the order of GBs.

* [mono][interp] Free mheader in case of inline failure

The header local types are not used anywhere so we can just free it.

src/mono/mono/mini/interp/transform.c

@@ -3103,6 +3103,7 @@ interp_inline_newobj (TransformData *td, MonoMethod *target_method, MonoMethodSi
 	int dreg, this_reg = -1;
 	int prev_sp_offset;
 	MonoClass *klass = target_method->klass;
+	MonoMethodHeader *mheader = NULL;
 
 	if (!(mono_interp_opt & INTERP_OPT_INLINE) ||
 			!interp_method_check_inlining (td, target_method, csignature))
@@ -3166,7 +3167,7 @@ interp_inline_newobj (TransformData *td, MonoMethod *target_method, MonoMethodSi
 	if (is_protected)
 		newobj_fast->flags |= INTERP_INST_FLAG_PROTECTED_NEWOBJ;
 
-	MonoMethodHeader *mheader = interp_method_get_header (target_method, error);
+	mheader = interp_method_get_header (target_method, error);
 	goto_if_nok (error, fail);
 
 	if (!interp_inline_method (td, target_method, mheader, error))
@@ -3180,6 +3181,7 @@ interp_inline_newobj (TransformData *td, MonoMethod *target_method, MonoMethodSi
 	push_var (td, dreg);
 	return TRUE;
 fail:
+	mono_metadata_free_mh (mheader);
 	// Restore the state
 	td->sp = td->stack + prev_sp_offset;
 	td->last_ins = prev_last_ins;
@@ -3214,10 +3216,14 @@ interp_constrained_box (TransformData *td, MonoClass *constrained_class, MonoMet
 static MonoMethod*
 interp_get_method (MonoMethod *method, guint32 token, MonoImage *image, MonoGenericContext *generic_context, MonoError *error)
 {
-	if (method->wrapper_type == MONO_WRAPPER_NONE)
+	if (method->wrapper_type == MONO_WRAPPER_NONE) {
 		return mono_get_method_checked (image, token, NULL, generic_context, error);
-	else
-		return (MonoMethod *)mono_method_get_wrapper_data (method, token);
+	} else {
+		MonoMethod *target_method = mono_method_get_wrapper_data (method, token);
+		if (generic_context)
+			target_method = mono_class_inflate_generic_method_checked (target_method, generic_context, error);
+		return target_method;
+	}
 }
 
 /*
@@ -3440,13 +3446,6 @@ interp_transform_call (TransformData *td, MonoMethod *method, MonoMethod *target
 			target_method = interp_get_method (method, token, image, generic_context, error);
 			return_val_if_nok (error, FALSE);
 			csignature = mono_method_signature_internal (target_method);
-
-			if (generic_context) {
-				csignature = mono_inflate_generic_signature (csignature, generic_context, error);
-				return_val_if_nok (error, FALSE);
-				target_method = mono_class_inflate_generic_method_checked (target_method, generic_context, error);
-				return_val_if_nok (error, FALSE);
-			}
 		}
 	} else {
 		csignature = mono_method_signature_internal (target_method);
@@ -3654,6 +3653,7 @@ interp_transform_call (TransformData *td, MonoMethod *method, MonoMethod *target
 			td->ip += 5;
 			goto done;
 		}
+		mono_metadata_free_mh (mheader);
 	}
 
 	/*