Cache compiled output-schema validators on ClientSession #3545

Job	Run time
checks / readme-snippets	13s
checks / docs	1m 4s
checks / test (3.14, locked, ubuntu-latest)	1m 21s
checks / pre-commit	53s
checks / test (3.14, lowest-direct, windows-latest)	1m 39s
checks / test (3.14, locked, windows-latest)	2m 38s
checks / test (3.10, lowest-direct, ubuntu-latest)	1m 21s
checks / test (3.12, locked, ubuntu-latest)	1m 42s
checks / test (3.10, locked, windows-latest)	1m 54s
checks / test (3.12, locked, windows-latest)	1m 51s
checks / test (3.10, locked, ubuntu-latest)	1m 32s
checks / test (3.13, lowest-direct, ubuntu-latest)	1m 17s
checks / test (3.11, locked, windows-latest)	1m 45s
checks / test (3.11, lowest-direct, ubuntu-latest)	1m 9s
checks / test (3.11, locked, ubuntu-latest)	1m 4s
checks / test (3.12, lowest-direct, ubuntu-latest)	1m 30s
checks / test (3.11, lowest-direct, windows-latest)	1m 51s
checks / test (3.12, lowest-direct, windows-latest)	1m 53s
checks / test (3.13, lowest-direct, windows-latest)	1m 59s
checks / test (3.13, locked, ubuntu-latest)	1m 14s
checks / test (3.14, lowest-direct, ubuntu-latest)	1m 24s
checks / test (3.13, locked, windows-latest)	2m 7s
checks / test (3.10, lowest-direct, windows-latest)	1m 53s
all-green	5s
	35m 19s

Provide feedback