checkClosure function signature mismatch in rts debug way on wasm32

When linking with -debug way of rts on wasm32, there is a linker warning:

wasm-ld: warning: function signature mismatch: checkClosure
>>> defined as (i32) -> void in /workspace/ghc/_build/stage1/lib/../lib/wasm32-wasi-ghc-9.5.20221214/rts-1.0.2/libHSrts-1.0.2_debug_p.a(ContinuationOps.debug_p_o)
>>> defined as (i32) -> i32 in /workspace/ghc/_build/stage1/lib/../lib/wasm32-wasi-ghc-9.5.20221214/rts-1.0.2/libHSrts-1.0.2_debug_p.a(Sanity.debug_p_o)

It's due to how ContinuationOps.cmm calls checkClosure. GHC infers the C function signature to have no return value, which is actually not the case at its definition site. Fixing it is pretty straightforward, one needs to add an _unused return value to the checkClosure call site, there's an example in Apply.cmm already.