[Attributor] Use the BumpPtrAllocator in InformationCache as well

We now also use the BumpPtrAllocator from the Attributor in the
InformationCache. The lifetime of objects in either is pretty much the
same and it should result in consistently good performance regardless of
the allocator.

Doing so requires to call more constructors manually but so far that
does not seem to be problematic or messy.

---

Single run of the Attributor module and then CGSCC pass (oldPM)
for SPASS/clause.c (~10k LLVM-IR loc):

Before:
```
calls to allocation functions: 615359 (368257/s)
temporary memory allocations: 83315 (49859/s)
peak heap memory consumption: 75.64MB
peak RSS (including heaptrack overhead): 163.43MB
total memory leaked: 269.04KB
```

After:
```
calls to allocation functions: 613042 (359555/s)
temporary memory allocations: 83322 (48869/s)
peak heap memory consumption: 75.64MB
peak RSS (including heaptrack overhead): 162.92MB
total memory leaked: 269.04KB
```

Difference:
```
calls to allocation functions: -2317 (-68147/s)
temporary memory allocations: 7 (205/s)
peak heap memory consumption: 2.23KB
peak RSS (including heaptrack overhead): 0B
total memory leaked: 0B

---