Properly drop overwritten ex data #622

Job	Run time
rustfmt	11s
clippy	1m 9s
Test FIPS integration	2m 13s
Test (stable)	3s
Cross build from macOS to Linux (x86_64-unknown-linux-gnu)	5m 16s
Test (macos-x86_64)	1s
Cross build from macOS to Linux (FIPS) (x86_64-unknown-linux-gnu)	6m 25s
Test features	1m 19s
Test (arm-android)	1m 35s
Test (arm64-android)	1m 31s
Test (i686-android)	1m 10s
Test (x86_64-android)	1s
Test (aarch64-ios)	1s
Test (aarch64-ios-sim)	1s
Test (x86_64-ios)	1s
Test (i686-linux)	16s
Test (arm-linux)	1m 11s
Test (aarch64-linux)	1m 26s
Test (x86_64-musl)	1s
Test (x86_64-mingw)	1s
Test (i686-msvc)	2s
Test (x86_64-msvc)	1s
	23m 55s

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