Kill wORDS_BIGENDIAN and replace it with platformByteOrder (#17957)

compiler/GHC/Cmm/Info.hs

compiler/GHC/Cmm/Utils.hs

compiler/GHC/CmmToC.hs

compiler/GHC/Llvm/Types.hs

compiler/GHC/Runtime/Heap/Inspect.hs

configure.ac

distrib/configure.ac.in

hadrian/cfg/system.config.in

hadrian/src/Rules/Generate.hs

includes/ghc.mk

libraries/ghc-boot/GHC/Platform.hs

libraries/ghc-boot/GHC/Settings.hs

mk/config.mk.in

utils/deriveConstants/Main.hs