[feat] Improved Iterative Deepening Searcher #906

Job	Run time
Coverage (STP)	47m 39s
Docker	16m 30s
Coverage (Z3)	50m 3s
clang-format	5m 50s
Linux (LLVM 14)	16m 25s
macOS	11m 8s
Linux (LLVM 13)	15m 45s
Linux (LLVM 12)	15m 54s
Linux (LLVM 11, Doxygen)	16m 47s
Linux (LLVM 10)	15m 42s
Linux (LLVM 9)	14m 36s
Linux (ASan)	51m 27s
Linux (UBSan)	58m 24s
Linux (MSan)	56m 37s
Linux (Z3 only)	24m 17s
Linux (metaSMT)	38m 43s
Linux (STP master)	21m 57s
Linux (Latest klee-uclibc)	20m 18s
Linux (Asserts disabled)	15m 28s
Linux (No TCMalloc, optimised runtime)	17m 33s
	8h 51m 3s

Provide feedback