Fix #7386: Measurement tooltip for tunnels, aqueducts & docks did not display or flickered.

Measurement tooltip was auto-closed as the hover/right-click test for tooltips was not
satisfied in this case. This is fixed by keeping the tooltip visible and instead explicitly
closing the tooltip when the PlaceObject is cancelled/completed.

Fix: Missing m8 data in console when using Query tool

When map array 8 was added, the Query tool wasn't updated to also
print the value there to the console, in debug builds.

Fix #6938: Don't change company value to perform cost estimations (#6939)

These meddling kids dared to play with magic, but the ancients texts
weren't ready for that.
Refactors logic to estimate costs that dated to even before OpenTTD 0.1;

Codechange: Avoid call to memcpy using null pointer in TooltipsWindow constructor

Strictly speaking, calling memcpy with src as a nullptr is undefined behaviour
and the optimiser is entitled to delete any null ptr checks which occur afterwards.
This removes the warning emitted by UndefinedBehaviorSantizer.

(svn r23525) -Codechange: make Window::flags4 WindowFlags instead of uint16, with only values known in WindowFlags (and move out 2 timers to their own variable)
-Codechange: rename Window::flags4 to Window::flags
-Codechange: move some non-inline functions from .hpp to .cpp