Fix an issue with unsorted `deleteat` #356

Job	Run time
Julia 1.8 - ubuntu-latest - x64	22m 17s
Julia 1.8 - ubuntu-latest - x86	29m 43s
Julia 1.8 - macOS-latest - x64	26m 19s
Julia 1.8 - windows-latest - x64	24m 28s
Julia 1.8 - windows-latest - x86	32m 31s
Julia 1 - ubuntu-latest - x64	21m 24s
Julia 1 - ubuntu-latest - x86	27m 35s
Julia 1 - macOS-latest - x64	20m 59s
Julia 1 - windows-latest - x64	23m 4s
Julia 1 - windows-latest - x86	29m 26s
Julia nightly - ubuntu-latest - x64	4m 0s
Julia nightly - macOS-latest - x64	4m 27s
Julia nightly - windows-latest - x64	4m 49s
	4h 31m 2s

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