[CI] standardize endif() calls in CMake scripts (#9637)

jvm-packages/CMakeLists.txt

@@ -7,13 +7,13 @@ list(APPEND JVM_SOURCES
 if (USE_CUDA)
   list(APPEND JVM_SOURCES
     ${PROJECT_SOURCE_DIR}/jvm-packages/xgboost4j-gpu/src/native/xgboost4j-gpu.cu)
-endif (USE_CUDA)
+endif()
 
 add_library(xgboost4j SHARED ${JVM_SOURCES} ${XGBOOST_OBJ_SOURCES})
 
 if (ENABLE_ALL_WARNINGS)
   target_compile_options(xgboost4j PUBLIC -Wall -Wextra)
-endif (ENABLE_ALL_WARNINGS)
+endif()
 
 target_link_libraries(xgboost4j PRIVATE objxgboost)
 target_include_directories(xgboost4j