Revert "[lldb] Add 'modify' type watchpoints, make it default (#66308)"

TestStepOverWatchpoint.py and TestUnalignedWatchpoint.py are failing
on the ubuntu and debian bots
https://lab.llvm.org/buildbot/#/builders/68/builds/60204
https://lab.llvm.org/buildbot/#/builders/96/builds/45623

and the newly added test TestModifyWatchpoint.py does not
work on windows bot
https://lab.llvm.org/buildbot/#/builders/219/builds/5708

I will debug tomorrow morning and reland.

This reverts commit 3692267c.