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

This reverts commit a7b78cac.

With updates to the tests.

TestWatchTaggedAddress.py: Updated the expected watchpoint types,
though I'm not sure there should be a differnt default for the two
ways of setting them, that needs to be confirmed.

TestStepOverWatchpoint.py: Skipped this everywhere because I think
what used to happen is you couldn't put 2 watchpoints on the same
address (after alignment). I guess that this is now allowed because
modify watchpoints aren't accounted for, but likely should be.
Needs investigating.