MCSAT: Preprocessor: fix equality simplification for mixed real-integer terms #289

Job	Run time
ubuntu-latest\|debug\|--enable-mcsat\|CC=gcc CXX=g++	7m 22s
ubuntu-latest\|debug\|--enable-mcsat\|CC=clang CXX=clang++	7m 47s
ubuntu-latest\|debug\|--enable-thread-safety\|CC=gcc CXX=g++	3m 46s
ubuntu-latest\|debug\|--enable-thread-safety\|CC=clang CXX=clang++	3m 42s
ubuntu-latest\|release\|--enable-mcsat\|CC=gcc CXX=g++	4m 40s
ubuntu-latest\|release\|--enable-mcsat\|CC=clang CXX=clang++	4m 58s
ubuntu-latest\|release\|--enable-thread-safety\|CC=gcc CXX=g++	2m 6s
ubuntu-latest\|release\|--enable-thread-safety\|CC=clang CXX=clang++	3m 53s
ubuntu-latest\|gcov\|--enable-mcsat\|CC=gcc CXX=g++	7m 2s
ubuntu-latest\|debug\|--enable-thread-safety --enable-mcsat\|CC=gcc CXX=g++	7m 23s
	52m 39s

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