Nested merge key with inline map broken

[stevenwdv]

(I finally took some time to submit some bugs with regard to the merge of #2400)

Describe the bug

Nested inline merge keys are broken. For an yq script I have it'd be really useful to have these work!

Version of yq: 4.53.2

Command
The command you ran:

echo '{<<: {<<: {a: 42}}}' | yq --yaml-fix-merge-anchor-to-spec 'explode(.)'

Actual behaviour

{}

Expected behaviour

{a: 42}

Additional context

Related to #2386.

This was fixed in #2400, but broke following a change of the order of merged keys before merge. I see that I documented the cause (fixedReconstructAliasedMap) there.

The issue seems to only affect explode, not traverse.