Pass -DLLDB_DISABLE_CURSES to the lldb-x86_64-debian bot
Tests which require curses functionality are mysteriously failing on
this bot, even though the bot does have curses installed, and the tests
pass everywhere else.
This patch hard-disables curses functionality on this bot to prevent the
failing tests from being run.
Reviewers: teemperor, jankratochvil
Differential Revision: https://reviews.llvm.org/D67075