`--no-check` produces malformed module

This is effectively moved from https://github.com/WebAssembly/testsuite/issues/132 to here.

In short, compiling the following module with wat2wasm and --no-check:

(module 
  (func (export "test") 
    (data.drop 0))) 

leads to a WASM module that contains no data count section. According to the official specification, if a module uses data.drop or memory.init, it needs to contain a data count section.

Arguably this entire situation is bogus simply because we need to compile with --no-check for this to even compile. Interestingly enough though this seems to be only situation where --no-check leads a malformed and not an invalid module. In this case that causes some confusion when strictly interpreting the testsuite test cases w.r.t. if a module should fail to parse or fail to validate.

Reproduce the issue with wat2wasm, --no-check, and the WAT module shown in the report. Trace how data.drop is handled during module emission and check the existing compiler tests for a suitable regression case. Done means the generated module follows the specification's data-count requirement, with test coverage for this input.