message: fix(build/emitter): indent only for non-empty line
diff: @@ -65,7 +65,7 @@ function createTextWriter(newLine: string) {
  }
  function write(s: string) {
  - if (lineStart) {
  + if (s && lineStart) {
  output += getIndentString(indent);
  lineStart = false;
  }
  