simple bump heuristic #308

Job	Run time
ubuntu-latest\|debug\|--enable-mcsat\|CC=gcc CXX=g++	6m 40s
ubuntu-latest\|debug\|--enable-mcsat\|CC=clang CXX=clang++	6m 46s
ubuntu-latest\|debug\|--enable-thread-safety\|CC=gcc CXX=g++	3m 18s
ubuntu-latest\|debug\|--enable-thread-safety\|CC=clang CXX=clang++	3m 44s
ubuntu-latest\|release\|--enable-mcsat\|CC=gcc CXX=g++	4m 21s
ubuntu-latest\|release\|--enable-mcsat\|CC=clang CXX=clang++	4m 42s
ubuntu-latest\|release\|--enable-thread-safety\|CC=gcc CXX=g++	1m 58s
ubuntu-latest\|release\|--enable-thread-safety\|CC=clang CXX=clang++	2m 17s
ubuntu-latest\|gcov\|--enable-mcsat\|CC=gcc CXX=g++	6m 45s
ubuntu-latest\|debug\|--enable-thread-safety --enable-mcsat\|CC=gcc CXX=g++	6m 29s
	47m 0s

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