compiler: don't use address of temporary for deferred delete

compiler: don't use address of temporary for deferred delete

    This CL corrects the handling of a deferred delete in a loop, to not
    use a temporary whose value will, at deferred execution time, wind up
    being the last value in the loop.

    The test for this is TestDeferDeleteSlow in the 1.11 runtime package.

    Reviewed-on: https://go-review.googlesource.com/135358

From-SVN: r264325