Update to LCG_98python3_ATLAS_4
Tested locally that a AthenaExternals build with this update to LCG_98python3_ATLAS_4 works fine.
More details in https://sft.its.cern.ch/jira/browse/SPI-1777 and https://gitlab.cern.ch/sft/lcgcmake/-/blob/LCG_98/cmake/toolchain/heptools-98python3_ATLAS_4.cmake
This should address the gperftools (https://its.cern.ch/jira/browse/ATEAM-691) and pprof issues (https://its.cern.ch/jira/browse/ATLINFR-3904)