PostgreSQL: Fix node\Tests\NodeCreationTest

So this test fails due to the PHP PDO pgsql driver with doing a LIKE query on a bytea field. There is an attempt at workaround already there but it does not work.

  public function prepareQuery($query) {
    // mapConditionOperator converts LIKE operations to ILIKE for consistency
    // with MySQL. However, Postgres does not support ILIKE on bytea (blobs)
    // fields.
    // To make the ILIKE operator work, we type-cast bytea fields into text.
    // @todo This workaround only affects bytea fields, but the involved field
    //   types involved in the query are unknown, so there is no way to
    //   conditionally execute this for affected queries only.
    return parent::prepareQuery(preg_replace('/ ([^ ]+) +(I*LIKE|NOT +I*LIKE) /i', ' ${1}::text ${2} ', $query));
  }

I tried doing the CONVERT_FROM inside the Connection class but to no success. So patched the query for this single test. Really we shouldn't be using serialized PHP. See #839444: Make serializer customizable for Cache\DatabaseBackend

Use PHP to filter the log messages.

So in Postgres 9 they added the Hex format for bytea. ::text with PDO driver will use the hex format and hence using a LIKE on ::text for bytea fields doesn't work for postgres 9

What other places is the preg_replace hack used on LIKE conditions?

It all looks good to me.
I can confirm that the test fails for postgreSQL and with the patch the test passes for postgreSQL.
So for me it is RTBC.

Let's add a comment as to why this method is as complex as it is.

Looks good to me.

Comment looks good. I don't see a nice way to fix this without a lot more changes. Committed/pushed to 8.0.x, thanks!