[WebAssembly] Unstackify registers with no uses in ExplicitLocals (#149626)

There are cases we end up removing some intructions that use stackified
registers after RegStackify. For example,

```wasm
bb.0:
  %0 = ...    ;; %0 is stackified
  br_if %bb.1, %0
bb.1:
```

In this code, br_if will be removed in CFGSort, so we should unstackify
%0 so that it can be correctly dropped in ExplicitLocals.

Rather than handling this in case-by-case basis, this PR just
unstackifies all stackifies register with no uses in the beginning of
ExplicitLocals, so that they can be correctly dropped.

Fixes #149097.

0 files changed, 0 insertions, 0 deletions