Remove unused test datafiles

These datafiles were no longer used by any test, remove since they
will otherwise just linger in there.

src/test/regress/data/bad_data2.data

-10|10|10
-11|11
-12
-13|
-14|14|14|14
-15|15|15
-16|16|16
-17|17|bad
-bad|18|18
-19|19|19
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src/test/regress/data/dept.data

-toy	sharon
-shoe	bob

src/test/regress/data/exttab1B.data

-'01-FEB-1970'|11|1.1|entry  1 is okay
-'02/05/1971'|22|2.2 |entry  2 : second  entry is also fine
-"01-FEB-1972'|33|3.3|entry  3 : thrid entry, nonmatching  quotes but PostgreSQL's and GPDB's copy figures it out
-'30-FEB-1973'|44|4.4|entry  4 : February never has thirty days (Should not be entered into table)
-'30-JAN-1974'|55|5.5|entry  5 : too many  columns (Should not be entered into table)'|64|35|2532.23
-'30-JAN-1975'|entry         6 : too few  columns (Should not be entered into table)
-'30-JAN-1976'|6.2|6.6|entry 7 :  Decimal in integer (Should not be entered into table)'
-'02-JAN-1977'|1E5|7.7|entry 8 : Non number character in integer (Should not be entered into table)'
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