optimize appending assertion functions to module
optimize appending assertion functions to module

Previously, we'd add each assertion to the module individually. This
requires remapping the same values in the module, once for each
assertion function.

Now we add all assertion functions at once, right before writing out the
module.

tclin914/sexpr-wasm-prototype-64,tclin914/sexpr-wasm-prototype-64,tclin914/sexpr-wasm-prototype-64,tclin914/sexpr-wasm-prototype-64,citisolo/wabt,WebAssembly/sexpr-wasm-prototype,citisolo/wabt,tclin914/sexpr-wasm-prototype-64,WebAssembly/wabt,WebAssembly/sexpr-wasm-prototype,citisolo/wabt,WebAssembly/sexpr-wasm-prototype,WebAssembly/sexpr-wasm-prototype,WebAssembly/wabt,citisolo/wabt,WebAssembly/wabt,WebAssembly/sexpr-wasm-prototype,citisolo/wabt,citisolo/wabt,WebAssembly/wabt,WebAssembly/sexpr-wasm-prototype,WebAssembly/wabt