Remove THRUST_WRAPPED_NAMESPACE and tests (#1578)

Fixes #1577. Removes the no-longer-necessary duplications of tests for `THRUST_WRAPPED_NAMESPACE` 

Wrapping the Thrust namespace is no longer required as of CCCL 2.3 (but is still available if needed). RMM is adopting CCCL 2.5 in release 24.08. 

Eliminating these tests improves build time and reduces testing time by 50%.

Authors:
  - Mark Harris (https://github.com/harrism)

Approvers:
  - Lawrence Mitchell (https://github.com/wence-)
  - Bradley Dice (https://github.com/bdice)
  - Michael Schellenberger Costa (https://github.com/miscco)

URL: #1578

tests/CMakeLists.txt

@@ -104,11 +104,6 @@ function(ConfigureTest TEST_NAME)
   ConfigureTestInternal("${PTDS_TEST_NAME}" ${_RMM_TEST_UNPARSED_ARGUMENTS})
   target_compile_definitions("${PTDS_TEST_NAME}" PUBLIC CUDA_API_PER_THREAD_DEFAULT_STREAM)
 
-  # Test with custom thrust namespace
-  string(REGEX REPLACE "_TEST$" "_NAMESPACE_TEST" NS_TEST_NAME "${TEST_NAME}")
-  ConfigureTestInternal("${NS_TEST_NAME}" ${_RMM_TEST_UNPARSED_ARGUMENTS})
-  target_compile_definitions("${NS_TEST_NAME}" PUBLIC THRUST_WRAPPED_NAMESPACE=rmm_thrust)
-
   foreach(name ${TEST_NAME} ${PTDS_TEST_NAME} ${NS_TEST_NAME})
     rapids_test_add(
       NAME ${name}