[infra] Check to see if addr2line exists before symbolization

Change-Id: If0709604d05beb4e41d7e412b39412debab733f6
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/611040
Reviewed-by: Ben Wagner <bungeman@google.com>
Commit-Queue: Ben Wagner <bungeman@google.com>
diff --git a/infra/bots/recipe_modules/flavor/resources/symbolize_stack_trace.py b/infra/bots/recipe_modules/flavor/resources/symbolize_stack_trace.py
index 78cf48e..826c198 100644
--- a/infra/bots/recipe_modules/flavor/resources/symbolize_stack_trace.py
+++ b/infra/bots/recipe_modules/flavor/resources/symbolize_stack_trace.py
@@ -23,6 +23,14 @@
         logs.append(line)
     proc.wait()
     print('Command exited with code %s' % proc.returncode)
+
+    try:
+        subprocess.check_call(['addr2line', '--help'])
+    except OSError:
+        print('addr2line not found on PATH. Skipping symbolization.')
+        return
+
+
     # Stacktraces generally look like:
     # /lib/x86_64-linux-gnu/libc.so.6(abort+0x16a) [0x7fa90e8d0c62]
     # /b/s/w/irISUIyA/linux_vulkan_intel_driver_debug/./libvulkan_intel.so(+0x1f4d0a) [0x7fa909eead0a]