[ruby-cvs:78484] 08074eb712 (master): Revert "Revert nil error and adding deprecation message"

NARUSE, Yui	2019-12-04 01:26:28 +0900 (Wed, 04 Dec 2019)

  New Revision: 08074eb712

  https://github.com/ruby/ruby/commit/08074eb712

  Log:
    Revert "Revert nil error and adding deprecation message"
    
    This reverts commit 452bee3ee8d68059fabd9b1c7a75661b14e3933e.

  Modified files:
    re.c
    spec/ruby/core/regexp/match_spec.rb
    test/ruby/test_regexp.rb