test: update interactive_tarantool for dbgr tests

The following changes were applied to `interactive_tarantool` helper
to adapt it for debugger tests:
* compared commands are now stripped from tabs and color codes too
* now each command independent of control symbols is being stripped
  before comparison in `execute_command()`
* created internal new function that is called from both `new()` and
  `new_debugger()`
* now user defined prompt can be set up from `new` and `new_debugger()`
* now there are several less typos in comments

Part of #7738

NO_CHANGELOG=test helper update
NO_DOC=test helper update
NO_TEST=test helper update