arch-arm: Revert 'Setup TC/ISA at construction time..'

Reverts:

dd2f1fb2f8520849f10fc25fc5eab5beaa90a7d4
https://gem5-review.googlesource.com/c/public/gem5/+/65174

and

47bd56ee71ba1d684138365e7123aa779989ba1d
https://gem5-review.googlesource.com/c/public/gem5/+/65291

The 47bd56ee change resulted in the
`SuiteUID:tests/gem5/fs/linux/arm/test.py:realview-switcheroo-noncaching-timing-ALL-x86_64-opt`
nightly test stalling. This behavior can be reproduced with:

```
./build/ALL/gem5.opt tests/gem5/fs/linux/arm/run.py tests/gem5/configs/realview-switcheroo-noncaching-timing.py tests/gem5/resources/arm “$(pwd)”
```

The subsequent change, dd2f1fb2, must be reverted for this change to be
reverted.

Change-Id: I6fed74f33d013f321b93cf1a73eee404cb87ce18
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/65732
Reviewed-by: Jason Lowe-Power <power.jg@gmail.com>
Maintainer: Bobby Bruce <bbruce@ucdavis.edu>
Tested-by: kokoro <noreply+kokoro@google.com>
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/65971
Reviewed-by: Bobby Bruce <bbruce@ucdavis.edu>
4 files changed