Don't generate same-named imports in fact modules (#6783)

Ensure that all imports have unique module/name combos to ensure that
the module can be instantiable in JS where separate functions need to be
provided for each import.

crates/environ/src/fact.rs

@@ -262,7 +262,7 @@ impl<'a> Module<'a> {
  let memory = memory.as_ref().map(|memory| {
  self.import_memory(
  "memory",
- "",
+ &format!("m{}", self.imported_memories.len()),
  MemoryType {
  minimum: 0,
  maximum: None,
@@ -279,7 +279,12 @@ impl<'a> Module<'a> {
  ValType::I32
  };
  let ty = self.core_types.function(&[ptr, ptr, ptr, ptr], &[ptr]);
- self.import_func("realloc", "", ty, func.clone())
+ self.import_func(
+ "realloc",
+ &format!("f{}", self.imported_funcs.len()),
+ ty,
+ func.clone(),
+ )
  });
 
  AdapterOptions {