base: Rename TestFiber into SwitchingFiber

This is done since TestFiber is too generic and it is not the only
Fiber's testing subclass in the unit test

Change-Id: Idc386f487091ae9bdadae865090a6719a25583da
Signed-off-by: Giacomo Travaglini <giacomo.travaglini@arm.com>
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/19153
Reviewed-by: Gabe Black <gabeblack@google.com>
Maintainer: Gabe Black <gabeblack@google.com>
Tested-by: kokoro <noreply+kokoro@google.com>
1 file changed