Support Oracles multibyte datatype statements

[vvursT]

Oracle supports special multibyte datatypes to be able to save unicode characters within a "not unicode charset database instance" (see http://www.orafaq.com/wiki/NVARCHAR2 for example)

Statements with that N' notation aren't parsed properly by the SqlStatementBuilder and are interpreted as multiline statement thus the migration will fail. The given test example will also fail:

assertFalse(new OracleSqlStatementBuilder()
.endsWithOpenMultilineStringLiteral("INSERT INTO nvarchar2_test VALUES ( N'qwerty' )"));

[vvursT]

Thanks to https://github.com/shadev who discovered this issue!