Remove redundant reserve call #569

Job	Run time
stable (ubuntu-latest)	1m 21s
stable (macos-latest)	1m 33s
stable (windows-latest)	2m 25s
loom	3m 31s
cross (i686-unknown-linux-gnu)	29s
minrust	3m 26s
cross (armv7-unknown-linux-gnueabihf)	51s
miri	27s
cross (powerpc-unknown-linux-gnu)	34s
nightly	4m 36s
cross (powerpc64-unknown-linux-gnu)	29s
rustfmt	7s
cross (wasm32-unknown-unknown)	6s
tsan	3m 51s
Publish Documentation	3m 16s
	27m 2s

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