Add `header_register_callback` builtin support (#1101) #371

Job	Run time
jammy/g++/c++17/asan=off/ubsan=off	6m 35s
focal/clang++/c++17/asan=off/ubsan=on	6m 33s
focal/g++-10/c++20/asan=on/ubsan=off	7m 38s
	20m 46s

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