Field Type Pass for system fields

[nhovratov]

If field type Pass is used for system fields like tstamp Content Blocks generates a new SQL definition for this field even though this should be handled by Core.

Expectation would be that Content Blocks ignores system fields and doesn't generate SQL for them.

Solution: Check if TcaSchema can be used to determine system fields.

Workarounds:

• set useExistingField: true this will prevent SQL generation
• Explicitly define tstamp in ext_tables.sql