pgsql: Move thread_test directory from /tools to /test so source-only

Log Message:
-----------
Move thread_test directory from /tools to /test so source-only tarballs
have the directory for the configure test.

Modified Files:
--------------
    pgsql:
        configure (r1.475 -> r1.476)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/configure.diff?r1=1.475&r2=1.476)
        configure.in (r1.445 -> r1.446)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/configure.in.diff?r1=1.445&r2=1.446)
    pgsql/src/include:
        pg_config.h.in (r1.91 -> r1.92)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/include/pg_config.h.in.diff?r1=1.91&r2=1.92)

Added Files:
-----------
    pgsql/src/test/thread:
        Makefile (r1.1)

(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/test/thread/Makefile?rev=1.1&content-type=text/x-cvsweb-markup)
        README (r1.1)

(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/test/thread/README?rev=1.1&content-type=text/x-cvsweb-markup)
        thread_test.c (r1.1)

(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/test/thread/thread_test.c?rev=1.1&content-type=text/x-cvsweb-markup)

Removed Files:
-------------
    pgsql/src/tools/thread:
        Makefile
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/tools/thread/Makefile)
        README
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/tools/thread/README)
        thread_test.c
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/tools/thread/thread_test.c)