roachtest: use m5, not m5d, for restore 8tb test

This works around cockroachdb#98783:

```
Instance type
c5.2xlarge
```

Now the roachtest runs on standard EBS volumes (provisioned to 125mb/s,
i.e. pretty weak ones):

```
$ df -h /mnt/data1/
Filesystem      Size  Used Avail Use% Mounted on
/dev/nvme1n1    2.0T  4.0G  2.0T   1% /mnt/data1
$ sudo nvme list | grep nvme1n1
/dev/nvme1n1     vol065ed9110066bb362 Amazon Elastic Block Store               1           2.15  TB /   2.15  TB    512   B +  0 B   1.0
```

Let's see how this fares.

The theory is that the test previously failed failed due to RAID0
because some nodes would unpredictably be slower than others (depending
on the striping, etc, across the raided inhomogeneous volumes), which we
don't handle well. Now, there's symmetry and hopefully things will be
slower (since we only have 125mb/s per volume now) but functional, i.e.
no more OOMs.

I verified this via

```
./pkg/cmd/roachtest/roachstress.sh -c 10 restore/tpce/8TB/aws/nodes=10/cpus=8 -- --cloud aws --parallelism 1
```

Epic: CRDB-25503
Release note: None

pkg/cmd/roachtest/tests/restore.go

@@ -312,7 +312,7 @@ func registerRestore(r registry.Registry) {
 		},
 		{
 			// The nightly 8TB Restore test.
-			hardware: makeHardwareSpecs(hardwareSpecs{nodes: 10, volumeSize: 2000}),
+			hardware: makeHardwareSpecs(hardwareSpecs{cpus: 8, nodes: 10, volumeSize: 2000}),
 			backup: makeBackupSpecs(backupSpecs{
 				version:  "v22.2.1",
 				workload: tpceRestore{customers: 500000}}),
@@ -411,7 +411,17 @@ func (hw hardwareSpecs) makeClusterSpecs(r registry.Registry) spec.ClusterSpec {
 	if hw.mem != spec.Auto {
 		clusterOpts = append(clusterOpts, spec.Mem(hw.mem))
 	}
-	return r.MakeClusterSpec(hw.nodes, clusterOpts...)
+	s := r.MakeClusterSpec(hw.nodes, clusterOpts...)
+	if s.Cloud == "aws" && s.VolumeSize != 0 && s.Mem != spec.Low {
+		// Work around an issue that RAID0s local NVMe and GP3 storage together:
+		// https://github.com/cockroachdb/cockroach/issues/98783.
+		//
+		// This should be removed once we have found a real solution that avoids
+		// ever creating such a RAID.
+		s.InstanceType = spec.AWSMachineType(s.CPUs, s.Mem)
+		s.InstanceType = strings.Replace(s.InstanceType, "d.", ".", 1)
+	}
+	return s
 }
 
 // String prints the hardware specs. If verbose==true, verbose specs are printed.