Negative Sampling test needs whole GPU (#4636)

Increase negative sampling test percentage to 100, allowing it to have an entire GPU.

This should correct intermittent C++ unit test failures in CI.

Authors:
  - Chuck Hastings (https://github.com/ChuckHastings)

Approvers:
  - Seunghwa Kang (https://github.com/seunghwak)

URL: #4636

cpp/tests/CMakeLists.txt

@@ -490,7 +490,7 @@ ConfigureTest(SAMPLING_POST_PROCESSING_TEST sampling/sampling_post_processing_te
 
 ###################################################################################################
 # - NEGATIVE SAMPLING tests --------------------------------------------------------------------
-ConfigureTest(NEGATIVE_SAMPLING_TEST sampling/negative_sampling.cpp)
+ConfigureTest(NEGATIVE_SAMPLING_TEST sampling/negative_sampling.cpp PERCENT 100)
 
 ###################################################################################################
 # - Renumber tests --------------------------------------------------------------------------------