Use libcontainer execseal to run ldconfig

This change copies ldconfig into a memfd before executing it from
the createContainer hook.

Signed-off-by: Evan Lezar <elezar@nvidia.com>

vendor/github.com/opencontainers/runc/libcontainer/system/rlimit_linux.go

@@ -0,0 +1,15 @@
+//go:build go1.23
+
+package system
+
+import (
+	"syscall"
+)
+
+// ClearRlimitNofileCache clears go runtime's nofile rlimit cache. The argument
+// is process RLIMIT_NOFILE values. Relies on go.dev/cl/588076.
+func ClearRlimitNofileCache(lim *syscall.Rlimit) {
+	// Ignore the return values since we only need to clean the cache,
+	// the limit is going to be set via unix.Prlimit elsewhere.
+	_ = syscall.Setrlimit(syscall.RLIMIT_NOFILE, lim)
+}