sanitycheck: log errors when executing binaries

Add some verbosity into the log file to help with debugging.

Signed-off-by: Anas Nashif <anas.nashif@intel.com>

scripts/sanitycheck

@@ -564,6 +564,7 @@ class BinaryHandler(Handler):
                                   env.get("ASAN_OPTIONS", "")
             if not self.lsan:
                 env["ASAN_OPTIONS"] += "detect_leaks=0"
+
         with subprocess.Popen(command, stdout=subprocess.PIPE,
                               stderr=subprocess.PIPE, cwd=self.build_dir, env=env) as proc:
             logger.debug("Spawning BinaryHandler Thread for %s" % self.name)
@@ -575,6 +576,9 @@ class BinaryHandler(Handler):
                 t.join()
             proc.wait()
             self.returncode = proc.returncode
+            (stdout, stderr) = proc.communicate(timeout=30)
+            if stderr:
+                logger.error(stderr.decode())
 
         handler_time = time.time() - start_time