Revert "ask the fixture set for the sql statements" to address #13356

This pull request addresses a kind of regression failure reported in #13356 and  rsim/oracle-enhanced#391 by reverting commit 026d0555685087845b74dd87a0417b5a164b1c13.

```ruby
$ cd activerecord
$ ARCONN=oracle ruby -Itest test/cases/fixtures_test.rb -n test_binary_in_fixtures
Using oracle
Run options: -n test_binary_in_fixtures --seed 36745

# Running:

F

Finished in 1.152086s, 0.8680 runs/s, 0.8680 assertions/s.

  1) Failure:
FixturesTest#test_binary_in_fixtures [test/cases/fixtures_test.rb:248]:
--- expected
+++ actual
@@ -1,20 +1 @@
-"\xFF\xD8\xFF\xE0\x00\x10JFIF\x00\x01\x01\x01\x00H\x00H\x00\x00\xFF\xDB\x00C\x00\r\t\t
-
... snip ...
```

After revertng 026d0555685087845b74dd87a0417b5a164b1c13 All sqlite3, mysql, mysql2 and postgresql adapter unit tests have passed. Since Rails 4.1 is coming soon, I want to Oracle enhanced adapter support Rails 4.1 soon.