Fix the definition of assignment-target.

Fixes issue 1166.
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Created by MOE: http://code.google.com/p/moe-java
MOE_MIGRATED_REVID=58000465
Remove the RemoveTryCatch pass.
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Created by MOE: http://code.google.com/p/moe-java
MOE_MIGRATED_REVID=58015747
[Fuzzer] Wrapping JavaScript programs in try-catch block to better format the runtime errors
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Created by MOE: http://code.google.com/p/moe-java
MOE_MIGRATED_REVID=58040230