Merge #11879: [tests] remove redundant univalue_tests.cpp

Merge #11879: [tests] remove redundant univalue_tests.cpp

2862b56 [tests] remove redundant univalue_tests.cpp (John Newbery)

Pull request description:

  univalue unit tests were added in #4730 , and exist at `/src/test/univalue_tests.cpp` (outside the univalue tree). That test was brought into the univalue repository in https://github.com/bitcoin-core/univalue/pull/4 , which was pulled into the github repository in https://github.com/bitcoin/bitcoin/pull/11420.

  That means that the univalue test exists in two places:
  1. `/src/test/univalue_tests.cpp`
  2. `/src/univalue/test/object.cpp`

  (2) is a strict superset of (1). It adds some macros to work around boost not being a univalue dependency, and adds a few extra lines of test.

  Therefore remove `/src/test/univalue_tests.cpp`

Tree-SHA512: 3747b10bbf62e9f12363905488b29945ad559ddca68c5c03d8a362de612a51f408f41a04d3712c6889bfc1632fb1a5fa0d7df0fbf02c322b3981a6d698f501b0