This reverts commit ace88542.

That commit disabled repl in tarantool for debugger console session
because debugger console wasn't compatible with Tarantool console,
i.e. this code hang in terminal:

```lua
tarantool> dbg = require 'luadebug'
tarantool> dbg()
```

With the previous patch in the patchset, full readline support and
console compatibility was introduced. Thus, no need to disable repl.

Part of #7738

NO_TEST=internal
NO_DOC=internal, revert unpublished
NO_CHANGELOG=internal

(cherry picked from commit 3774e85d)