Give correct error message for `expect {}.not_to raise_error(/foo/)` #818

Job	Run time
Rubocop	23s
Ruby 2.7 (Windows)	4m 28s
Legacy Ruby Builds (2.1.9)	1m 9s
Ruby 2.6 (Windows)	2m 17s
Ruby 3.3	2m 30s
Legacy Ruby Builds (2.0)	1m 10s
Ruby 2.5 (Windows)	3m 6s
Ruby 3.2	2m 15s
Legacy Ruby Builds (1.9.3)	1m 18s
Ruby 2.4 (Windows)	2m 18s
Ruby 3.1	2m 14s
Legacy Ruby Builds (1.9.2)	1m 51s
Ruby 2.3 (Windows)	2m 10s
Ruby 3.0	2m 36s
Legacy Ruby Builds (1.8.7)	1m 9s
Ruby 2.7	3m 50s
Ruby 2.2 (Windows)	2m 15s
Legacy Ruby Builds (REE)	1m 19s
Ruby 2.6	3m 48s
Legacy Ruby Builds (JRuby 1.7)	4m 2s
Ruby 2.5	3m 40s
Legacy Ruby Builds (JRuby 1.7 1.8 mode)	3m 31s
Ruby 2.4	2m 13s
Legacy Ruby Builds (JRuby 9.1.17.0)	4m 53s
Ruby 2.3	2m 25s
Ruby 2.2	2m 47s
Ruby ruby-head	31s
Ruby jruby-9.2.13.0	7m 6s
Ruby 2.7 with diff-lcs 1.3	3m 46s
Ruby 2.7 with diff-lcs 1.4.3	3m 40s
	1h 20m 40s

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