Ignore invalid utf-8 characters in symbolize.py

Currently symbolize.py will crash when handling invalid UTF-8
characters. This happens when an Android application outputs
extended characters such as "\xC0".

Here is a simple test case of this issue:
    printf "TESTTEST\xC0TESTTEST"|symbolize.py

Since in most cases we don't control application's output, it's
better making the code resilient to those characters.

Test: Ran the above test case and verified no more crashes.
Change-Id: I82929ea11223b97e67862188b23157825ce38549
1 file changed