Boostable-into is a mistake

• Prevent operation counters from running if boostable_into is allowed
• Introduce language version 2018.2 to turn on ignore_boostable_into by default
• Exclude concurrent inames from get_iname_duplication_options because they are never explicitly 'entered'

@dokempf Could you review this, particularly 2c83fe9b?

@jdsteve2 This should help a bit with your recent issues.

cc @kaushikcfd