Nested blocks in loops are not moved to top level

[vaadin-bot]

Originally by @hesara

---

Unnesting does not take place correctly in the following SCSS:

.outer {
  .v-ie8 & {
    @for $i from 1 through 1 {
      .top {
        x: $i;
      }
    }
  }
}

Vaadin Sass compiler produces

.v-ie8 .outer {
    .top {
    x: 1;
}
}

instead of the correct

.v-ie8 .outer .top {
  x: 1;
}

---

Imported from https://dev.vaadin.com/ issue #14097

[vaadin-bot]

Originally by @hesara

---

Simpler example:

.outer {
  @for $i from 1 through 1 {
    .inner {
      x: $i;
    }
  }
}

should produce

.outer .inner {
  x: 1;
}