Mem optimize #854

Job	Run time
Docker	11m 17s
Coverage (STP)	41m 56s
Linux (LLVM 14)	24m 19s
clang-format	5m 41s
Linux (LLVM 13)	15m 9s
Coverage (Z3)	41m 7s
macOS	13m 24s
Linux (LLVM 12)	22m 30s
Linux (LLVM 11, Doxygen)	19m 30s
Linux (LLVM 10)	16m 37s
Linux (LLVM 9)	19m 32s
Linux (ASan)	51m 55s
Linux (UBSan)	17m 33s
Linux (MSan)	40m 52s
Linux (Z3 only)	15m 53s
Linux (metaSMT)	42m 13s
Linux (STP master)	15m 50s
Linux (Latest klee-uclibc)	16m 33s
Linux (Asserts disabled)	16m 7s
Linux (No TCMalloc, optimised runtime)	15m 19s
	7h 43m 17s

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