PR go/78763

	PR go/78763
    compiler: call determine_types even for constant expressions

    We need to call determine_types even for constant expressions, since a
    constant expression may include code like unsafe.Sizeof(0).  Something
    needs to determine the type of the untyped 0, and that should be the
    determine_types pass.

    Implementing that triggered a compiler crash on test/const1.go because
    it permitted some erroneous constants to make it all the way to the
    backend.  Catch that case by checking whether we get a constant
    overflow error, and marking the expression invalid if we do.  This is
    a good change in any case, as previously we reported the same constant
    overflow error multiple times, and now we only report it once.

    Fixes GCC PR 78763.

    Reviewed-on: https://go-review.googlesource.com/34496

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@243729 138bc75d-0d04-0410-961f-82ee72b054a4