Initialize the address-significance table fragment's layout order.
Initialize the address-significance table fragment's layout order.

This fragment is created after layout, which is where the order
normally gets set.

Should fix a test failure under msan.

git-svn-id: 0ff597fd157e6f4fc38580e8d64ab130330d2411@340516 91177308-0d34-0410-b5e6-96231b3b80d8

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