Enable tools/retrace.py on windows

The module resource is not accessible on windows.

Bug: 148472880
Change-Id: I11167a0a16a38d1c3e7f719e8d4114f0b974b870
diff --git a/build.gradle b/build.gradle
index d4f2a0f..bce1569 100644
--- a/build.gradle
+++ b/build.gradle
@@ -1822,7 +1822,10 @@
         result.exception.printStackTrace(processIn)
         processIn.flush()
         processIn.close()
-        process.waitFor()
+        if (process.waitFor() != 0) {
+            out.append("ERROR DURING RETRACING\n")
+            out.append(err.toString())
+        }
         out.append("\n\n--------------------------------------\n")
         out.append("OBFUSCATED STACKTRACE\n")
         out.append("--------------------------------------\n")