- Add new `WasmInstr` constructor `WasmSqrt` for sqrt, corresponding to
primitivie operations in wasm.
- When lowering CallishMachOp, use `WasmAbs` and `WasmSqrt` for F32 and
F64 fabs and sqrt.
(cherry picked from commit 64b0d4d0)
(cherry picked from commit d6b9dab5)