pgsql: Suppress compiler warning in new regex match-all detection code.

Suppress compiler warning in new regex match-all detection code.

gcc 10 is smart enough to notice that control could reach this
"hasmatch[depth]" assignment with depth < 0, but not smart enough
to know that that would require a badly broken NFA graph. Change
the assert() to a plain runtime test to shut it up.

Per report from Andres Freund.

Discussion: /messages/by-id/20210223173437.b3ywijygsy6q42gq@alap3.anarazel.de

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/3db05e76f92846d4b54d7de251b0875cf1e23aa4

Modified Files
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src/backend/regex/regc_nfa.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)