Back out D66983, "[WebAssembly] Add wasm-specific vector shuffle builtin and
Fix shuffle intrinsic tests. Since they are compiled with -O2 masks need to be
updated as well, otherwise optimizer would replace second operand with
Don't revert shuffle intrinsic codegen tests, instead convert them to use
`shufflevector`. This also requires some mask updates to avoid invalid
`shufflevector` use and to make sure both operands get picked up.
This reverts commit 8e3e56f2a36701480eeb65e426701d5a9025cc59.