[WebAssembly] Fix selection of global calls

When selecting calls, currently we unconditionally remove `Wrapper`s of
the call target. But we are supposed to do that only when the target is
a function, an external symbol (= library function), or an alias of a
function. Otherwise we end up directly calling globals that are not
functions.

Fixes https://github.com/llvm/llvm-project/issues/60003.

Reviewed By: tlively, HerrCai0907

Differential Revision: https://reviews.llvm.org/D147397