pgsql: Make ExplainPropertyInteger accept 64bit input,remove *Long var

Make ExplainPropertyInteger accept 64bit input, remove *Long variant.

'long' is not useful type across platforms, as it's 32bit on 32 bit
platforms, and even on some 64bit platforms (e.g. windows) it's still
only 32bits wide.

As ExplainPropertyInteger should never be performance critical, change
it to accept a 64bit argument and remove ExplainPropertyLong.

Author: Andres Freund
Discussion: https://postgr.es/m/20180314164832.n56wt7zcbpzi6zxe@alap3.anarazel.de

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/f3e4b95edb6cbf0cd41dc9ff0c884bfdc425e6fb

Modified Files
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contrib/file_fdw/file_fdw.c    |  4 +--
src/backend/commands/explain.c | 71 +++++++++++++++++++++---------------------
src/include/commands/explain.h |  4 +--
3 files changed, 39 insertions(+), 40 deletions(-)