[NEW TYPE INFERENCE] Don't tighten types of values defined locally.
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Created by MOE: http://code.google.com/p/moe-java
MOE_MIGRATED_REVID=65164385
Add an exception in CheckNullableReturn so that "return arr[i] || null;" is still considered nullable.

Also add a comment to let people know that the check is still experimental.
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Created by MOE: http://code.google.com/p/moe-java
MOE_MIGRATED_REVID=65191192
[NEW TYPE INFERENCE] Check the declared type of the lhs of a for-in
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Created by MOE: http://code.google.com/p/moe-java
MOE_MIGRATED_REVID=65191498
[NEW TYPE INFERENCE] Ignore debugger statements during type inference.
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Created by MOE: http://code.google.com/p/moe-java
MOE_MIGRATED_REVID=65200370
[NEW TYPE INFERENCE] Handle constant variables.
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Created by MOE: http://code.google.com/p/moe-java
MOE_MIGRATED_REVID=65211085
Spacing/imports
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Created by MOE: http://code.google.com/p/moe-java
MOE_MIGRATED_REVID=65215459