Remove dependency on Quick/Nimble

[yoichitgy]

This PR addresses the same issue of Swinject Issue #472, and performs the migration from Quick/Nimble to XCTest in the same way as Swinject PR #473.

• Replaced XxxSpec using Quick/Nimble with XxxTests using XCTest.
• Removed dependency on Quick/Nimble. (We still need Carthage because of the dependency on Swinject.)

Note A few unit tests that check throwing precondition were commented out because those cannot be tested without depending on Nimble or CwlPreconditionTesting. I prioritized migration to XCTest and reducing dependency this time for easier maintainability as stated in #472.

[yoichitgy]

@mpdifran Thank you for the review😃