Simpleperf: remove abort in child process.

Bug: 22328419
Change-Id: I3521a246929c10dc1eb9c9dac75240197b5b0a40
diff --git a/simpleperf/workload.cpp b/simpleperf/workload.cpp
index f8e4edd..999e315 100644
--- a/simpleperf/workload.cpp
+++ b/simpleperf/workload.cpp
@@ -93,10 +93,11 @@
     TEMP_FAILURE_RETRY(write(exec_child_fd, &exec_child_failed, 1));
     close(exec_child_fd);
     errno = saved_errno;
-    PLOG(FATAL) << "execvp(" << argv[0] << ") failed";
+    PLOG(ERROR) << "execvp(" << argv[0] << ") failed";
   } else {
-    PLOG(FATAL) << "child process failed to receive start_signal, nread = " << nread;
+    PLOG(DEBUG) << "child process failed to receive start_signal, nread = " << nread;
   }
+  exit(1);
 }
 
 bool Workload::Start() {