Fix specifying the dependency from SYSCALL_DEBUG to $strError() function. (#25032)

Fix specifying the dependency from SYSCALL_DEBUG to $strError() function
to take place directly where the use of strError() is emitted, and not
indirectly via the JS SYSCALLS object. Fixes WASMFS + SYSCALLS_DEBUG
build mode, e.g. in test wasmfs.test_fs_nodefs_rw.

Author: juj

src/lib/libcore.js

@@ -2559,6 +2559,8 @@ function wrapSyscallFunction(x, library, isWasi) {
   post += "}\n";
   post += "dbg(`syscall return: ${ret}`);\n";
   post += "return ret;\n";
+  // Emit dependency to strError() since we added use of it above.
+  library[x + '__deps'].push('$strError');
 #endif
   delete library[x + '__nothrow'];
   var handler = '';

src/lib/libsyscall.js

@@ -9,9 +9,6 @@ var SyscallsLibrary = {
 #if FILESYSTEM && SYSCALLS_REQUIRE_FILESYSTEM
                    '$PATH',
                    '$FS',
-#endif
-#if SYSCALL_DEBUG
-                   '$strError',
 #endif
   ],
   $SYSCALLS: {