Enable jemalloc profiling #543

Job	Run time
Additional Builds and Concurrency Tests	14m 0s
Basic Checks	20m 24s
miri	3m 10s
Measure coverage	28m 44s
Release builds and tests	11m 47s
sanitize (address)	17m 40s
Slow tests	19m 58s
sanitize (address, multi-threading)	19m 25s
sanitize (leak)	7m 47s
sanitize (leak, multi-threading)	8m 35s
	2h 31m 30s

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