[lld][WebAssembly] Add `--no-growable-memory` (#82890)

We recently added `--initial-heap` - an option that allows one to up the
initial memory size without the burden of having to know exactly how
much is needed.

However, in the process of implementing support for this in Emscripten
(https://github.com/emscripten-core/emscripten/pull/21071), we have
realized that `--initial-heap` cannot support the use-case of
non-growable memories by itself, since with it we don't know what to set
`--max-memory` to.

We have thus agreed to move the above work forward by introducing
another option to the linker (see
https://github.com/emscripten-core/emscripten/pull/21071#discussion_r1491755616),
one that would allow users to explicitly specify they want a
non-growable memory.

This change does this by introducing `--no-growable-memory`: an option
that is mutally exclusive with `--max-memory` (for simplicity - we can
also decide that it should override or be overridable by `--max-memory`.
In Emscripten...