Accept "Closed Resultset" raised by ojdbc11 21.21

After bumping the 11g matrix to Instant Client 21.21 and switching to
ojdbc11.jar shipped inside that zip, the driver raises
"Java::JavaSql::SQLException: Closed Resultset: next" when fetching
from a closed cursor (lowercase 's' in "Resultset"). The previous
ojdbc11 23.26 used "Closed ResultSet" (uppercase 'S') which the spec's
regex matched.

Add the /i flag so both casings — and any future case variant of the
same message — match.

Author: yahonda

spec/plsql/procedure_spec.rb

@@ -1875,7 +1875,7 @@ def new_candidate(status)
       expect(plsql.test_cursor do |cursor|
         cursor2 = cursor
       end).to be_nil
-      expect { cursor2.fetch }.to raise_error(/Cursor was already closed|Closed Statement|Closed ResultSet/)
+      expect { cursor2.fetch }.to raise_error(/Cursor was already closed|Closed Statement|Closed ResultSet/i)
     end
 
     it "should not raise error if cursor is closed inside block" do