pgsql: Remove _configthreadlocale() calls in ecpg test suite.

Remove _configthreadlocale() calls in ecpg test suite.

This essentially reverts commits a772624b1 and 04fbe0e45, which
added "_configthreadlocale(_ENABLE_PER_THREAD_LOCALE)" calls to the
thread-related ecpg test programs.  That was nothing but a hack,
because we shouldn't expect that ecpg-using applications have
done that for us; and now that we've inserted such calls into
ecpglib, the tests should still pass without it.

(If they don't, it would be good to know that.)

HEAD only; there seems no big need to change this in the
back branches.

Discussion: https://postgr.es/m/22937.1548307384@sss.pgh.pa.us

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/e3565fd61cee16414a682d2be0d44c112a80a30c

Modified Files
--------------
src/interfaces/ecpg/test/expected/thread-alloc.c   | 24 ++++------
.../ecpg/test/expected/thread-descriptor.c         | 14 ++----
src/interfaces/ecpg/test/expected/thread-prep.c    | 52 ++++++++++------------
src/interfaces/ecpg/test/expected/thread-thread.c  | 28 +++++-------
.../ecpg/test/expected/thread-thread_implicit.c    | 28 +++++-------
src/interfaces/ecpg/test/thread/alloc.pgc          |  6 ---
src/interfaces/ecpg/test/thread/descriptor.pgc     |  6 ---
src/interfaces/ecpg/test/thread/prep.pgc           |  6 ---
src/interfaces/ecpg/test/thread/thread.pgc         |  6 ---
.../ecpg/test/thread/thread_implicit.pgc           |  6 ---
10 files changed, 58 insertions(+), 118 deletions(-)