Fuzz

Add `consteval` hmac testing and collected fixes for extents and byte sizing #470

Job	Run time
posix (clang, clang++-16, 20, ubuntu-22.04, clang-16, deb http://apt.llvm.org/jammy/ llvm-toolcha...	9m 49s
posix (clang, clang++-17, 20, ubuntu-22.04, clang-17, deb http://apt.llvm.org/jammy/ llvm-toolcha...	9m 57s
posix (clang, clang++-18, 20,23, ubuntu-24.04, clang-18, deb http://apt.llvm.org/noble/ llvm-tool...	18m 44s
posix (clang, clang++-19, 20,23, ubuntu-24.04, clang-19, deb http://apt.llvm.org/noble/ llvm-tool...	19m 34s
	58m 4s

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