UniquePtr: Support array for unique ptr. #1599

Job	Run time
cygwin64-cache	1m 44s
multiple-arch-aarch64	5m 39s
multiple-arch-armv7	5m 39s
utest-regression-blackbox-test	8m 26s
fast	1s
cygwin64	7m 54s
build-ubuntu20	1m 39s
build-ubuntu18	1m 24s
build-centos7	2m 13s
build-cross-aarch64	2m 18s
build-cross-arm	2m 27s
build-ubuntu16	1m 25s
coverage	2m 26s
multiple-arch-amd64	1m 12s
test-done	1s
	44m 28s

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