Mcsat ufnra model fix #454

Job	Run time
ubuntu-latest\|debug\|--enable-mcsat\|CC=gcc CXX=g++	8m 22s
ubuntu-latest\|debug\|--enable-mcsat\|CC=clang CXX=clang++	8m 38s
ubuntu-latest\|debug\|--enable-thread-safety\|CC=gcc CXX=g++	3m 48s
ubuntu-latest\|debug\|--enable-thread-safety\|CC=clang CXX=clang++	4m 31s
ubuntu-latest\|release\|--enable-mcsat\|CC=gcc CXX=g++	5m 44s
ubuntu-latest\|release\|--enable-mcsat\|CC=clang CXX=clang++	6m 0s
ubuntu-latest\|release\|--enable-thread-safety\|CC=gcc CXX=g++	2m 22s
ubuntu-latest\|release\|--enable-thread-safety\|CC=clang CXX=clang++	2m 38s
ubuntu-latest\|gcov\|--enable-mcsat\|CC=gcc CXX=g++	7m 58s
ubuntu-latest\|debug\|--enable-thread-safety --enable-mcsat\|CC=gcc CXX=g++	8m 14s
	58m 15s

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