pgsql: Fix how SJE checks against PHVs

Fix how SJE checks against PHVs

It seems that a PHV evaluated/needed at or below the self join should not have
a problem if we remove the self join. But this requires further investigation.
For now, we just do not remove self joins if the rel to be removed is laterally
referenced by PHVs.

Discussion: https://postgr.es/m/CAMbWs4-ns73VF9gi37q61G3dS6Xuos+HtryMaBh37WQn=BsaJw@mail.gmail.com
Author: Richard Guo

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/b7f315c9d7d839dda847b10d170ffec7c3f4dbba

Modified Files
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src/backend/optimizer/plan/analyzejoins.c | 4 ++--
src/test/regress/expected/join.out | 15 +++++++++++++++
src/test/regress/sql/join.sql | 6 ++++++
3 files changed, 23 insertions(+), 2 deletions(-)