Segmentation fault when launching binary from volume that is `noexec` on host

### Description

When a container is started with a host-mounted path marked noexec on the host, executing binaries from that folder inside the container results in a Segmentation fault.

### Steps to reproduce

1. Put some static binary in a folder on host that belongs to filesystem mounted with `noexec` option.
2. Add this path to container
3. Try to launch any binary from this folder in container

### runsc version

```shell
runsc version release-20260810.0
spec: 1.2.1
```

### docker version (if using docker)

```shell
Client: Docker Engine - Community
Version: 29.7.2
API version: 1.55
Go version: go1.26.5
Git commit: a7dcaa6
Built: Wed Aug 5 18:29:26 2026
OS/Arch: linux/amd64
Context: default

Server: Docker Engine - Community
Engine:
Version: 29.7.2
API version: 1.55 (minimum version 1.40)
Go version: go1.26.5
Git commit: 6a43e3d
Built: Wed Aug 5 18:29:26 2026
OS/Arch: linux/amd64
Experimental: false
containerd:
Version: v2.3.3
GitCommit: aad11006b869517fcd3009450b6f82da282e1a9b
runsc:
Version: release-20260810.0
GitCommit:
docker-init:
Version: 0.19.0
GitCommit: de40ad0
```

### uname

Linux 6.12.101+deb13-amd64

Start by reproducing the issue with runsc using a host-mounted path on a noexec filesystem, following the listed steps and environment details. Compare launching the static binary from that mount with launching it elsewhere; done means the noexec case no longer produces a segmentation fault and the behavior is covered by an appropriate regression check.

Written by the indexing model from the issue text.