pgsql: Fix inconsistent equalfuncs.c behavior for FuncCall.funcformat.

Fix inconsistent equalfuncs.c behavior for FuncCall.funcformat.

Other equalfuncs.c checks on CoercionForm fields use
COMPARE_COERCIONFORM_FIELD (which makes them no-ops),
but commit 40c24bfef neglected to make _equalFuncCall
do likewise. Fix that.

This is only strictly correct if FuncCall.funcformat has
no semantic effect, instead just determining ruleutils.c
display formatting. 40c24bfef added a couple of checks
in parse analysis that could break that rule; but on closer
inspection, they're redundant, so just take them out again.

Per report from Noah Misch.

Discussion: https://postgr.es/m/20210606063331.GC297923@rfd.leadboat.com

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/a65e9f3f1405b786673feec131879843432bf9a6

Modified Files
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src/backend/nodes/equalfuncs.c | 2 +-
src/backend/parser/parse_clause.c | 1 -
src/backend/parser/parse_func.c | 1 -
3 files changed, 1 insertion(+), 3 deletions(-)