Fix null pointer check elimination for catch entries.

Remove the special treatment of catch blocks for null
pointer check elimination and class initialization check
elimination. In both cases this can help optimizing
previously missed cases. In the null check case, this
avoids incorrect optimization as exposed by the new test.

Bug: 16230771
Change-Id: I834b7a1835d9ca8572f4f8d8516d93913c701ad1