fix edge cases in inputhandler methods

[jerch]

This PR addresses edge case handling for InputHandler methods. Currently many methods are still slightly off compared to xterm's behavior.

This PR shall enable passing most of the escape sequence files. Shall also fix #1434 and fix #2020. Shall give xterm.js much better results in vttest.

Things to rework:

• cursor positioning (see cursor at wrong column position behind last cell #1434 and Probably incorrect horizontal cursor positioning with certain CSI sequences #2020)
  Other than stated in cursor at wrong column position behind last cell #1434 I hope to get away with fixing cursor position issues on individual methods. Basic cursor positioning is done now with range checks. Closes Probably incorrect horizontal cursor positioning with certain CSI sequences #2020.
• Fixed REP: REP itself should also reset previous char
• tab positioning (all tab sequence files are failing)
  All except CBT working.
• CBT still not working: This is also related to margin/wrap handling and prolly fixable by a later PR. (Background: cursor restrictions are not correctly applied after RI + IND)
• cursor position sanity checks for:
  • EL
  • ED
  • DCH, ECH, ICH
• wrapping after escape code
• rework DECSTBM (all tests failing)
  We are slightly off in the margin handling for print, lineFeed and Terminal.scroll. Changes to those are more involved and better done with isolated PRs.

[jerch]

Gonna stop on this PR as it is already quite big.

Remaining issues:

• DECSTBM: We have margin handling issues in InputHandler.print, InputHandler.lineFeed and Terminal.scroll. Any changes to those are more involved, thus should be addressed in separate PRs. --> DECSTBM has margin issues #2306
• CBT: Only found one issue with it - cursor restrictions are not applied correctly after RI + IND. This particular issue is not fixable before dealing with the margin/wrap issues seen in DECSTBM. All other conditions seem to work correctly. --> DECSTBM has margin issues #2306
• DECOM: We did not respect origin mode at all, this PR does and passes vttest in this regard. Still the edgecases are not worked out yet. To be done with a separate PR.
• cursor handling: As pointed out by Create Cursor class #2290, we should unify the cursor stuff into better maintainable code. --> DECOM tests #2307
• ancient features: We have some limited support of ancient features in InputHandler that either make not much sense or even can mess with the integrators' embedding page (like DECCOLM). We should review those parts and prolly remove it from the core codebase (maybe it could live in a compat addon later on). --> eval usefulness of compat addon #2308

Up for review.