[OpenMP][AIX] Extend LIT test timeout limit (#93319)

When buildbots are crowded, the libomp LIT tests may hit timeouts so
extend the limit from 1800 to 3000 seconds.

Author: xingxue-ibm

openmp/cmake/OpenMPTesting.cmake

@@ -58,7 +58,7 @@ if (${OPENMP_STANDALONE_BUILD})
     set(DEFAULT_LIT_ARGS "${DEFAULT_LIT_ARGS} --no-progress-bar")
   endif()
   if (${CMAKE_SYSTEM_NAME} MATCHES "AIX")
-    set(DEFAULT_LIT_ARGS "${DEFAULT_LIT_ARGS} --time-tests --timeout=1800")
+    set(DEFAULT_LIT_ARGS "${DEFAULT_LIT_ARGS} --time-tests --timeout=3000")
   endif()
   set(OPENMP_LIT_ARGS "${DEFAULT_LIT_ARGS}" CACHE STRING "Options for lit.")
   separate_arguments(OPENMP_LIT_ARGS)