Fuzzer for STARTUPE2, ppips for CFG_CENTER_TOP/MID/BOT

[hansfbaier]

This contains a fuzzer for bits that only show up, when USRCCLKO is connected to
a non-constant net.
Also it turned out that the switchboxes on the CFG_CENTER tiles are all pseudo.
I have been able to get a working BSCANE2 with those,
and also a working STARTUPE2 test.
Since the other primitives are not that much different qualitatively,
I reckon most CFG_CENTER primitives should work with this.

[hansfbaier]

@tmichalak The CI failures here do not seem to have anything to do with the changes of the PR.

[mkurc-ant]

Hi. I can see from the logs that eg. for Kintex 7 065b-gtp-common-pips failed due to timeout:

2023-10-10T08:28:25.9523857Z �[32;1m08:28:25�[0m | 2023-10-10T08:28:25 - xc7a200tffg1156-1/065b-gtp-common-pips      - 1h47m: + echo 'ERROR: timeout'
2023-10-10T08:28:25.9524445Z �[32;1m08:28:25�[0m | 2023-10-10T08:28:25 - xc7a200tffg1156-1/065b-gtp-common-pips      - 1h47m: + exit 1
2023-10-10T08:28:25.9525127Z �[32;1m08:28:25�[0m | 2023-10-10T08:28:25 - xc7a200tffg1156-1/065b-gtp-common-pips      - 1h47m: make[2]: *** [../pip_loop.mk:68: run] Error 1
2023-10-10T08:28:25.9525729Z �[32;1m08:28:25�[0m | 2023-10-10T08:28:25 - xc7a200tffg1156-1/065b-gtp-common-pips      - 1h47m: 
2023-10-10T08:28:25.9526357Z �[32;1m08:28:25�[0m | 2023-10-10T08:28:25 - xc7a200tffg1156-1/065b-gtp-common-pips      - 1h47m: --------------------------------------------------------------------------
2023-10-10T08:28:25.9527018Z �[32;1m08:28:25�[0m | 2023-10-10T08:28:25 - xc7a200tffg1156-1/065b-gtp-common-pips      - 1h47m: !Failed! @ 2023-10-10T08:28:25.630697 with exit code: 2
2023-10-10T08:28:25.9527837Z �[32;1m08:28:25�[0m | 2023-10-10T08:28:25 - xc7a200tffg1156-1/065b-gtp-common-pips      - 1h47m: --------------------------------------------------------------------------
2023-10-10T08:28:25.9528457Z �[32;1m08:28:25�[0m | 2023-10-10T08:28:25 - xc7a200tffg1156-1/065b-gtp-common-pips      - 1h47m: WARNING: Fuzzer failed!
2023-10-10T08:28:25.9529065Z �[32;1m08:28:25�[0m | make[1]: *** [Makefile:191: 065b-gtp-common-pips/run.xc7a200tffg1156-1.ok] Error 2

This happens from time to time (fuzzer instability). I'll restart the CI. If it fails again more debugging will be needed.

[mkurc-ant]

The CI passed the 2nd time so indeed there is an instability in the other fuzzer. As for this one it looks good to me.