build: use the system provided LuaJIT on s390x #9756

Job	Run time
run-ubuntu-unit-tests (-DFLB_JEMALLOC=On, gcc)	13m 34s
run-ubuntu-unit-tests (-DFLB_JEMALLOC=On, clang)	13m 30s
run-ubuntu-unit-tests (-DFLB_JEMALLOC=Off, gcc)	12m 44s
run-ubuntu-unit-tests (-DFLB_JEMALLOC=Off, clang)	13m 15s
run-ubuntu-unit-tests (-DFLB_SMALL=On, gcc)	12m 49s
run-ubuntu-unit-tests (-DFLB_SMALL=On, clang)	13m 57s
run-ubuntu-unit-tests (-DSANITIZE_ADDRESS=On, gcc)	13m 8s
run-ubuntu-unit-tests (-DSANITIZE_ADDRESS=On, clang)	13m 9s
run-ubuntu-unit-tests (-DSANITIZE_UNDEFINED=On, gcc)	12m 59s
run-ubuntu-unit-tests (-DSANITIZE_UNDEFINED=On, clang)	13m 8s
run-ubuntu-unit-tests (-DFLB_COVERAGE=On, gcc)	45m 57s
run-ubuntu-unit-tests (-DFLB_SANITIZE_MEMORY=On, gcc)	12m 42s
run-ubuntu-unit-tests (-DFLB_SANITIZE_MEMORY=On, clang)	12m 51s
run-ubuntu-unit-tests (-DFLB_SANITIZE_THREAD=On, gcc)	12m 42s
run-ubuntu-unit-tests (-DFLB_SANITIZE_THREAD=On, clang)	12m 35s
run-macos-unit-tests (-DFLB_JEMALLOC=Off)	11m 49s
run-macos-unit-tests (-DFLB_SANITIZE_MEMORY=On)	13m 5s
run-macos-unit-tests (-DFLB_SANITIZE_THREAD=On)	12m 20s
Unit tests (matrix)	1s
	4h 26m 15s

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