pgsql: Further sync postgres_fdw's "Relations" output with the rest of

Further sync postgres_fdw's "Relations" output with the rest of EXPLAIN.

EXPLAIN generally only adds schema qualifications to table names when
VERBOSE is specified. In postgres_fdw's "Relations" output, table
names were always so qualified, but that was an implementation
restriction: in the original coding, we didn't have access to the
verbose flag at the time the string was generated. After the code
rearrangement of commit 4526951d5, we do have that info available
at the right time, so make this output follow the normal rule.

Discussion: https://postgr.es/m/12424.1575168015@sss.pgh.pa.us

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/bf39b3af6a9c6a036aae0742cf339fce662eee3a

Modified Files
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contrib/postgres_fdw/expected/postgres_fdw.out | 26 +++++++++++++-------------
contrib/postgres_fdw/postgres_fdw.c | 17 ++++++++++++-----
2 files changed, 25 insertions(+), 18 deletions(-)