Don't run the full inliner when passed -O3 -fplugin-arg-dragonegg-ir-optimize=0.
Fix incorrect line breaking before trailing block comments.

Before, clang-format would happily move a trailing block comment to a
new line, which normally changes the perceived binding of that comment.

E.g., it would move:
void f() { /* comment */
  ...
}
to:
void f() {
  /* comment */
  ...
}