First, ensure that whenever a bpf_spin_lock is present in an allocation,
the reg->id is preserved. This won't be true for global variables
however, since they have a single map value per map, hence the verifier
harcodes it to 0 (so that multiple pseudo ldimm64 insns can yield the
same lock object per map at a given offset).

Next, add test cases for all possible combinations (kptr, global, map
value, inner map value). Since we lifted restriction on locking in inner
maps, also add test cases for them. Currently, each lookup into an inner
map gets a fresh reg->id, so even if the reg->map_ptr is same, they will
be treated as separate allocations and the incorrect unlock pairing will
be rejected.
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20221118015614.2013203-22-memxor@gmail.comSigned-off-by: Alexei Starovoitov <ast@kernel.org>