Add test for post-quantum key exchange #5138

Job	Run time
msrv	1m 12s
lint	1m 30s
audit	20s
features (ubuntu-latest)	2h 4m 5s
test (ubuntu-latest, stable)	1m 46s
features (macos-latest)	27m 55s
test-android (x86_64-linux-android, x86_64, 26)	4m 11s
test (ubuntu-latest, beta)	1m 50s
features (windows-latest)	54m 28s
test-android (i686-linux-android, x86, 26)	4m 31s
test-aws-lc-rs	2m 53s
test (macos-latest, stable)	1m 29s
test (windows-latest, stable)	3m 53s
test on freebsd	3m 55s
test on netbsd	4m 50s
test on illumos	6m 1s
test on solaris	6m 55s
test wasm32-unknown-unknown	1m 0s
	4h 12m 44s

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