pgsql: Remove unused regression test files.

Remove unused regression test files.

euc_* and mule_internal test cases were identical to the ones in
src/test/mb. sql_ascii didn't exist elsewhere, but has been broken since
2001, and doesn't seem very interesting anyway. drop.sql hasn't been used
since 2000, when regress.sh was removed.

Branch
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master

Details
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http://git.postgresql.org/pg/commitdiff/d0cab7903bf695bf305bd4c01f99e0e28d233d91

Modified Files
--------------
src/test/regress/expected/euc_cn.out | 87 -------
src/test/regress/expected/euc_jp.out | 87 -------
src/test/regress/expected/euc_kr.out | 87 -------
src/test/regress/expected/euc_tw.out | 85 -------
src/test/regress/expected/mule_internal.out | 333 ---------------------------
src/test/regress/expected/sql_ascii.out | 87 -------
src/test/regress/sql/drop.sql | 246 --------------------
src/test/regress/sql/euc_cn.sql | 19 --
src/test/regress/sql/euc_jp.sql | 19 --
src/test/regress/sql/euc_kr.sql | 19 --
src/test/regress/sql/euc_tw.sql | 20 --
src/test/regress/sql/mule_internal.sql | 72 ------
src/test/regress/sql/sql_ascii.sql | 19 --
13 files changed, 0 insertions(+), 1180 deletions(-)