`lp.privatize_temporaries_with_inames` fails for multiple inames sweeping the same temporary

For the kernel:
```python
knl = lp.make_kernel(
"{[i,j]: 0<=i<10 and 10<=j<14}",
"""
for i
<> tmp = i
out[i] = tmp
end
for j
tmp = j
out[j] = tmp
end
""",
name="arange_14",
seq_dependencies=True)

lp.privatize_temporaries_with_inames(knl, {"i", "j"})
```

we get an error:
```
loopy.diagnostic.LoopyError: instruction 'insn' requires adding indices for privatizing var 'tmp' on iname(s) 'i', but previous instructions required inames 'j'
```