Support trace rewind

What does this MR do?

Based on: !2389 (merged)

This is done. It is manually tested

This adds a support for two additional status codes on UpdateJob:

• 202 indicates that UpdateJob got accepted, but it is not yet complete processing all data and Runner should continue retrying
• 412 indicates that Rails failed to validate required data and requested Runner to resend all trace

This updates the logic to support that workflow.

Why was this MR needed?

This is related to discussion about trace handling improvements for Runner: gitlab#232533 (comment 405974271).

This is needed to provide a better maintainability and explicitness of data processing for traces. This allows Rails to make Runner to resend the trace if it finds that it is incomplete on Rails side.