load REPL in test and copy `Base._kwdef!` #168

Job	Run time
test (1.6, x64, ubuntu-latest, false)	29s
test (1.6, x64, windows-latest, false)	10m 49s
test (1.6, x64, macOS-latest, false)	1m 1s
test (1.6, x86, ubuntu-latest, false)	31s
test (1.6, x86, windows-latest, false)	11m 2s
test (1, x64, ubuntu-latest, false)	43s
test (1, x64, windows-latest, false)	1m 15s
test (1, x64, macOS-latest, false)	1m 17s
test (1, x86, ubuntu-latest, false)	49s
test (1, x86, windows-latest, false)	1m 11s
test (nightly, ubuntu-latest, x64, true, true)	43s
	29m 50s

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