Fix for loop copy warning #3506

Job	Run time
ubuntu-clang-deprecated Debug	22m 49s
ubuntu-clang-deprecated Release	23m 55s
ubuntu-clang-quaternions Debug	22m 49s
ubuntu-clang-quaternions Release	24m 16s
ubuntu-clang-tbb Debug	24m 17s
ubuntu-clang-tbb Release	26m 1s
ubuntu-clang-cayleymap Debug	23m 31s
ubuntu-clang-cayleymap Release	23m 53s
ubuntu-clang-system-libs Debug	22m 54s
ubuntu-clang-system-libs Release	23m 35s
ubuntu-no-boost Debug	19m 7s
ubuntu-no-boost Release	19m 48s
ubuntu-no-unstable Debug	18m 58s
ubuntu-no-unstable Release	19m 31s
ubuntu-build-examples Debug	22m 49s
ubuntu-build-examples Release	24m 8s
	6h 2m 21s

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