fix registration-queue error in mcsat-model-hint #276

Job	Run time
ubuntu-latest\|debug\|--enable-mcsat\|CC=gcc CXX=g++	7m 17s
ubuntu-latest\|debug\|--enable-mcsat\|CC=clang CXX=clang++	7m 50s
ubuntu-latest\|debug\|--enable-thread-safety\|CC=gcc CXX=g++	3m 21s
ubuntu-latest\|debug\|--enable-thread-safety\|CC=clang CXX=clang++	4m 3s
ubuntu-latest\|release\|--enable-mcsat\|CC=gcc CXX=g++	4m 46s
ubuntu-latest\|release\|--enable-mcsat\|CC=clang CXX=clang++	4m 58s
ubuntu-latest\|release\|--enable-thread-safety\|CC=gcc CXX=g++	2m 2s
ubuntu-latest\|release\|--enable-thread-safety\|CC=clang CXX=clang++	2m 14s
ubuntu-latest\|gcov\|--enable-mcsat\|CC=gcc CXX=g++	7m 15s
ubuntu-latest\|debug\|--enable-thread-safety --enable-mcsat\|CC=gcc CXX=g++	7m 28s
	51m 14s

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