[BLUEJ-1305] Code completion shows duplicate entries for array length

If you create a variable with a type like String[] and do autocomplete, you will see multiple entries for "int length" -- five for String[]. The problem seems to be that we are picking up the definitions from all the "superclasses" (for array of Object,array of CharSequence, array of Comparable) and not realising that they are the same, or not correctly deduplicating.

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Issue metadata

• Issue type: Bug
• Priority: Medium