Unrolled build for #150708

Rollup merge of #150708 - Kobzol:merge-queue, r=marcoieni

Enable merge queue in new bors

We can proactively merge this now. Note that new bors will still default to being "paused" and not running the merge queue, after being restarted:
- https://github.com/rust-lang/bors/blob/e1fafaa3b89c225069fa2aa1193096e1d66075c3/src/bors/merge_queue.rs#L101
- https://github.com/rust-lang/bors/blob/bf491ee40d1fc877af273f2ec92a2968dee8cdb7/src/github/api/mod.rs#L159
- #112049 (comment)

We can resume it quickly with a command, to test how the merging functionality behaves.

Author: rust-timer

rust-bors.toml

@@ -29,8 +29,7 @@ labels_blocking_approval = [
 # If CI runs quicker than this duration, consider it to be a failure
 min_ci_time = 600
 
-# Flip this once new bors is used for actual merges on this repository
-merge_queue_enabled = false
+merge_queue_enabled = true
 report_merge_conflicts = true
 
 [labels]
@@ -55,7 +54,9 @@ try_failed = [
     "-S-waiting-on-review",
     "-S-waiting-on-crater"
 ]
-auto_build_succeeded = ["+merged-by-bors"]
+auto_build_succeeded = [
+    "+merged-by-bors"
+]
 auto_build_failed = [
     "+S-waiting-on-review",
     "-S-blocked",