Remove unnecessary MEMORY64 block (#18209)

The only reason this might be useful is of the EM_ASM block happens
to return a bigint, which, in general, should not be that case.

Author: sbc100

src/library.js

@@ -2979,11 +2979,7 @@ mergeInto(LibraryManager.library, {
 #if ASSERTIONS
     if (!ASM_CONSTS.hasOwnProperty(code)) abort('No EM_ASM constant found at address ' + code);
 #endif
-#if MEMORY64
-    return Number(ASM_CONSTS[code].apply(null, args));
-#else
     return ASM_CONSTS[code].apply(null, args);
-#endif
   },
 
   emscripten_asm_const_int__sig: 'ippp',