Merged patch series by Konstantin Osipov:
"These series improve uniqueness of generated timeuuids and change
list append/prepend logic to use client/LWT timestamp in timeuuids
generated for list keys. Timeuuid compare functions are
optimized.
The test coverage is extended for all of the above."
uuid: add a comment warning against UUID::operator<
uuid: replace slow versions of timeuiid compare with optimized/tested versions.
test: add tests for legacy uuid compare & msb monotonicity
test: add a test case for append/prepend limit
test: add a test case for monotonicity of timeuuid least significant bits
uuid: implement optimized timeuuid compare
test: add a test case for list prepend/append with custom timestamp
lists: rewrite list prepend to use append machinery
lists: use query timestamp for list cell values during append
uuid: fill in UUID node identifier part of UUID
test: add a CQL test for list append/prepend operations