fix dimassoc unit-test for DEBUGGING #4661

Job	Run time
linux (CFLAGS="-O1 -fno-omit-frame-pointer -fsanitize=address -fno-var-tracking" --disable-bindin...	7m 18s
linux (CC="clang")	6m 39s
linux-cmake	2m 7s
linux (--enable-release)	37m 4s
linux (--enable-gcov --disable-bindings --disable-docs CFLAGS="-O0 -g")	5m 25s
linux (--disable-write --disable-docs)	7m 12s
macOS	5m 58s
linux (CFLAGS="-O2 -m32" --disable-bindings --disable-docs)	13m 33s
linux (CFLAGS="-O2 -fno-omit-frame-pointer -fsanitize=undefined -fno-var-tracking" --disable-bind...	11m 11s
mingw	30m 9s
mips32-big-endian	9m 27s
mingw-cmake	3m 28s
ppc64-big-endian	13m 33s
vs2019	6m 7s
vs2019-ninja	4m 42s
	2h 43m 53s

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