Don't reset before_context_ivars in reset_memoized

[bootstraponline]

This isn't intended to be merged. Tracking down a potential memory issue related to #2095 I'm expecting this PR to fail on Travis.

[bootstraponline]

I expected to see the memory test fail, instead it's failing for some unknown reason.

1816 examples, 0 failures, 3 pending

The command "script/run_build" exited with 2.
https://travis-ci.org/rspec/rspec-core/jobs/87574215

[bootstraponline]

It looks like master is failing with the same error. I guess the issue is flaky tests. This change should be safe to merge then.

[bootstraponline]

lib/rspec/core/rake_task.rb
RSpec::Support.define_optimized_require_for_rspec(:core) { |f| require_relative "../#{f}" }

shows up as missing in the coverage report which explains the exit code.

[bootstraponline]

When I run locally on Ruby 2.2.3:

./script/rspec_with_simplecov spec --backtrace --format progress --profile --format progress

require_rspec_core is already defined so the unless block never executes (and counts against coverage).

[JonRowe]

👍