[MISched] Unify the way to specify scheduling direction (#119518)

For pre-ra scheduling, we use two options `-misched-topdown` and
`-misched-bottomup` to force the direction.

While for post-ra scheduling, we use `-misched-postra-direction`
with enumerated values (`topdown`, `bottomup` and `bidirectional`).

This is not unified and adds some mental burdens. Here we replace
these two options `-misched-topdown` and `-misched-bottomup` with
`-misched-prera-direction` with the same enumerated values.

To avoid the condition of `getNumOccurrences() > 0`, we add a new
enum value `Unspecified` and make it the default initial value.

These options are hidden, so we needn't keep the compatibility.

0 files changed, 0 insertions, 0 deletions