Mem optimize #846

Job	Run time
Docker	14m 57s
Coverage (STP)	38m 36s
clang-format	5m 41s
Linux (LLVM 14)	14m 48s
Coverage (Z3)	38m 21s
macOS	10m 57s
Linux (LLVM 13)	14m 48s
Linux (LLVM 12)	14m 50s
Linux (LLVM 11, Doxygen)	14m 49s
Linux (LLVM 10)	14m 51s
Linux (LLVM 9)	14m 29s
Linux (ASan)	14m 49s
Linux (UBSan)	9m 1s
Linux (MSan)	14m 50s
Linux (Z3 only)	1s
Linux (metaSMT)	14m 53s
Linux (STP master)	14m 48s
Linux (Latest klee-uclibc)	14m 56s
Linux (Asserts disabled)	14m 50s
Linux (No TCMalloc, optimised runtime)	12m 9s
	5h 7m 24s

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