Merge branch 'verifier-liveness-simplification'

Edward Cree says:

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The first patch is a simplification of register liveness tracking by using
 a separate parentage chain for each register and stack slot, thus avoiding
 the need for logic to handle callee-saved registers when applying read
 marks.  In the future this idea may be extended to form use-def chains.
The second patch adds information about misc/zero data on the stack to the
 state dumps emitted to the log at various points; this information was
 found essential in debugging the first patch, and may be useful elsewhere.
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Signed-off-by: Alexei Starovoitov <ast@kernel.org>