Try to substitute constructor chains for IPUTs.

Try to substitute constructor chains for IPUTs.

Match a constructor chain where each constructor either
forwards some or all of its arguments to the next (i.e.
superclass constructor or a constructor in the same class)
and may pass extra zeros (of any type, including null),
followed by any number of IPUTs on "this", storing either
arguments or zeros, until we reach the contructor of
java.lang.Object.

When collecting IPUTs from the constructor chain, remove
any IPUTs that store the same field as an IPUT that comes
later. This is safe in this case even if those IPUTs store
volatile fields because the uninitialized object reference
wasn't allowed to escape yet. Also remove any IPUTs that
store zero values as the allocated object is already zero
initialized.

Change-Id: If93022310bf04fe38ee741665ac4a65d4c2bb25f