tests: Removed SPARC Insttests from .testignore

Due to the fixing of the SPARC insttest binary, recorded here:
https://gem5-review.googlesource.com/c/public/gem5-resources/+/33396,
these tests now pass.

Change-Id: I4dca4504476f6d388e607a1075d44e9be69b5259
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/33138
Reviewed-by: Jason Lowe-Power <power.jg@gmail.com>
Maintainer: Jason Lowe-Power <power.jg@gmail.com>
Tested-by: kokoro <noreply+kokoro@google.com>
4 files changed