Accepts as valid responses to staged requests. #442

Job	Run time
B2 gcc-11	3m 5s
B2 msvc-14.2	5m 32s
CMake gcc-11 17 Debug	6m 45s
B2 clang-14	3m 16s
B2 msvc-14.3	4m 32s
CMake msvc-14.2 Debug C++17	6m 4s
CMake gcc-11 20 Release	7m 35s
CMake msvc-14.2 Release C++17	6m 20s
CMake clang-11 17 Debug	4m 27s
CMake msvc-14.3 Debug C++20	7m 15s
CMake clang-11 20 Debug	4m 42s
CMake msvc-14.3 Release C++20	7m 28s
CMake clang-13 17 Release	5m 52s
CMake clang-13 20 Release	6m 6s
CMake clang-14 17 Debug -stdlib=libc++	6m 26s
CMake clang-14 20 Release -stdlib=libc++	8m 3s
	1h 33m 28s

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