package-resolver should not optimize yarn.lock by default

[bestander]

Do you want to request a feature or report a bug?
feature

What is the current behavior?

If yarn.lock has this entry

babel-runtime@^6.0, babel-runtime@^6.0.0, babel-runtime@^6.11.6, babel-runtime@^6.9.0, babel-runtime@^6.9.1, babel-runtime@^6.9.2:
  version "6.18.0"
  resolved "https://registry.yarnpkg.com/babel-runtime/-/babel-runtime-6.18.0.tgz#0f4177ffd98492ef13b9f823e9994a02584c9078"
  dependencies:
    core-js "^2.4.0"
    regenerator-runtime "^0.9.5"

babel-runtime@^6.22.0:
  version "6.23.0"
  resolved "https://registry.yarnpkg.com/babel-runtime/-/babel-runtime-6.23.0.tgz#0a9489f144de70efb3ce4300accdb329e2fc543b"
  dependencies:
    core-js "^2.4.0"
    regenerator-runtime "^0.10.0"

Yarn would try to optimize it and use the highest compatible resolution everywhere, specifically after yarn install the lockfile will be optimized into

babel-runtime@^6.0, babel-runtime@^6.0.0, babel-runtime@^6.11.6, babel-runtime@^6.9.0, babel-runtime@^6.9.1, babel-runtime@^6.9.2, babel-runtime@^6.22.0:
  version "6.23.0"
  resolved "https://registry.yarnpkg.com/babel-runtime/-/babel-runtime-6.23.0.tgz#0a9489f144de70efb3ce4300accdb329e2fc543b"
  dependencies:
    core-js "^2.4.0"
    regenerator-runtime "^0.10.0"

And the packages will be installed 6.23 everywhere.

What is the expected behavior?

Yarn should respect yarn.lock that was generated earlier to achieve installation determinism.
Otherwise people will get unexpected changes to installation tree.

Please mention your node.js, yarn and operating system version.
Yarn 0.26