Mem optimize #863

Job	Run time
clang-format	5m 33s
Docker	13m 45s
Linux (LLVM 14)	21m 48s
Coverage (STP)	38m 27s
macOS	10m 54s
Coverage (Z3)	42m 33s
Linux (LLVM 13)	19m 34s
Linux (LLVM 12)	21m 8s
Linux (LLVM 11, Doxygen)	17m 37s
Linux (LLVM 10)	16m 38s
Linux (LLVM 9)	15m 41s
Linux (ASan)	49m 30s
Linux (UBSan)	46m 18s
Linux (MSan)	56m 27s
Linux (Z3 only)	15m 41s
Linux (metaSMT)	33m 16s
Linux (STP master)	19m 33s
Linux (Latest klee-uclibc)	17m 55s
Linux (Asserts disabled)	16m 3s
Linux (No TCMalloc, optimised runtime)	17m 59s
	8h 16m 20s

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