[swift-inspect] Limit number of jobs printed on an actor.

If we encounter bad data in the target, we could end up trying to print an infinite list of jobs. Clamp it to 1,000 so we fail more gracefully.

rdar://113417637

Author: mikeash

tools/swift-inspect/Sources/swift-inspect/Operations/DumpConcurrency.swift

@@ -421,10 +421,17 @@ fileprivate class ConcurrencyDumper {
         print("    no jobs queued")
       } else {
         print("    job queue: \(jobStr(job))")
-        while job != 0 {
+        let limit = 1000
+        for i in 1 ... limit {
           job = swift_reflection_nextJob(context, job);
           if job != 0 {
             print("               \(jobStr(job))")
+          } else {
+            break
+          }
+
+          if i == limit {
+            print("               ...truncated...")
           }
         }
       }