Merge branch 'bpf-stack-depth-tracking-fixes'

Alexei Starovoitov says:

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Jann reported an issue with stack depth tracking. Fix it and add tests.
Also fix off-by-one error in MAX_CALL_FRAMES check. This set is on top
of Jann's "selftest for late caller stack size increase" test.
====================

Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>