Remove remaining uses of __import decorator (#17975)

It looks they are not necessary anymore since #17411.
`__asyncify_state__import` and `__asyncify_data__import` were added
after that when #15893 landed, and `__c_longjmp_import` was a typo in
the first place (there is only one `_` instead of two `_`s before
`import`) so it was likely not detected when other uses were removed.

Author: aheejin

src/library.js

@@ -3623,13 +3623,10 @@ mergeInto(LibraryManager.library, {
 #endif
 #if SUPPORT_LONGJMP == 'wasm'
   __c_longjmp: "new WebAssembly.Tag({'parameters': ['{{{ POINTER_WASM_TYPE }}}']})",
-  __c_longjmp_import: true,
 #endif
 #if ASYNCIFY
   __asyncify_state: "new WebAssembly.Global({'value': 'i32', 'mutable': true}, 0)",
-  __asyncify_state__import: true,
   __asyncify_data: "new WebAssembly.Global({'value': 'i32', 'mutable': true}, 0)",
-  __asyncify_data__import: true,
 #endif
 #endif