Android: Treat broken test deobfuscation as fatal

Rather than silently not deobfuscating things.

Bug: 1081438
Change-Id: I263956d55b819db8a5c0dce269687e9d44c56d6b
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2204969Reviewed-by: Stephen Martinis <martiniss@chromium.org>
Commit-Queue: Andrew Grieve <agrieve@chromium.org>
Cr-Commit-Position: refs/heads/master@{#770102}

build/android/pylib/symbols/deobfuscator.py

@@ -150,7 +150,7 @@ class DeobfuscatorPool(object):
 
       # De-obfuscation is broken.
       if self._num_restarts == _MAX_RESTARTS:
-        return lines
+        raise Exception('Deobfuscation seems broken.')
 
       # Restart any closed Deobfuscators.
       for i, d in enumerate(self._pool):