add and use request->local_dict #10467

Job	Run time
pre-ci	9s
master-self-ubuntu24-linux-gcc	9m 16s
master-self-ubuntu24-linux-gcc-ndebug	8m 57s
master-self-ubuntu24-linux-gcc-O2-g3	9m 20s
master-self-ubuntu24-linux-clang	5m 15s
master-self-ubuntu24-linux-clang-lean	5m 15s
master-self-ubuntu24-linux-gcc-lean	8m 55s
master-self-ubuntu24-linux-clang-O2-g3	5m 18s
master-self-ubuntu24-linux-clang-ndebug	4m 53s
master-self-ubuntu24-linux-clang-altlibs	4m 59s
master-self-ubuntu24-linux-fuzzer	8m 2s
Merge into upstream	0s
	1h 10m 19s

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