Fix mcsat array optimization #435

Job	Run time
ubuntu-latest\|debug\|--enable-mcsat\|CC=gcc CXX=g++	8m 27s
ubuntu-latest\|debug\|--enable-mcsat\|CC=clang CXX=clang++	8m 43s
ubuntu-latest\|debug\|--enable-thread-safety\|CC=gcc CXX=g++	4m 4s
ubuntu-latest\|debug\|--enable-thread-safety\|CC=clang CXX=clang++	4m 25s
ubuntu-latest\|release\|--enable-mcsat\|CC=gcc CXX=g++	5m 35s
ubuntu-latest\|release\|--enable-mcsat\|CC=clang CXX=clang++	5m 25s
ubuntu-latest\|release\|--enable-thread-safety\|CC=gcc CXX=g++	2m 34s
ubuntu-latest\|release\|--enable-thread-safety\|CC=clang CXX=clang++	2m 42s
ubuntu-latest\|gcov\|--enable-mcsat\|CC=gcc CXX=g++	8m 7s
ubuntu-latest\|debug\|--enable-thread-safety --enable-mcsat\|CC=gcc CXX=g++	8m 18s
	58m 20s

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