simpleperf: fix a bug setting symfs dir.

Bug: 119438870
Test: run simpleperf_unit_test.
Test: run simpleperf manually.

Change-Id: I2f7ca659dc3a9833650f326ff5560fef44e769a5
diff --git a/simpleperf/cmd_report_test.cpp b/simpleperf/cmd_report_test.cpp
index 03a67bd..a767030 100644
--- a/simpleperf/cmd_report_test.cpp
+++ b/simpleperf/cmd_report_test.cpp
@@ -351,6 +351,11 @@
   ASSERT_NE(content.find("main"), std::string::npos);
 }
 
+TEST_F(ReportCommandTest, report_without_symfs_dir) {
+  TemporaryFile tmpfile;
+  ASSERT_TRUE(ReportCmd()->Run({"-i", GetTestData(PERF_DATA), "-o", tmpfile.path}));
+}
+
 TEST_F(ReportCommandTest, report_sort_vaddr_in_file) {
   Report(PERF_DATA, {"--sort", "vaddr_in_file"});
   ASSERT_TRUE(success);