Remove broken conflict benchmarks

[dylanahsmith]

Problem

I was trying to run our benchmarks, since I wanted to make sure recent refactors didn't cause a performance regression. However, it looks like they got broken because they were doing some monkey patching of the private resolve_cache_miss method that got removed in the refactor.

Running dev benchmark-cpu resulted in this error in the output

FetchEmbedConflictRunner:             /Users/dylansmith/src/identity_cache/performance/cache_runner.rb:114:in `method': undefined method `resolve_cache_miss' for class `#<Class:0x007fcf86b92460>' (NameError)
	from /Users/dylansmith/src/identity_cache/performance/cache_runner.rb:114:in `prepare'
	from ./performance/cpu.rb:14:in `run'
	from ./performance/cpu.rb:27:in `block in benchmark'
	from ./performance/cpu.rb:25:in `each'
	from ./performance/cpu.rb:25:in `benchmark'
	from ./performance/cpu.rb:36:in `bmbm'
	from ./performance/cpu.rb:44:in `<main>'

Solution

I just removed these conflict benchmarks, since the only difference they have is that they cause the cas or add memcached operations to fail, but identity cache doesn't have any code conditional on whether or not these operations succeed. As such, it was only really benchmarking dependencies of identity cache.

[dylanahsmith]

This started overriding the above exclude under the jobs: key

[fbogsany]

The benchmarks were originally added to compare perf with CAS against the corresponding Miss results. See #154 (comment) for discussion. They're not really useful as regression tests.