syscall: don't use INODE64 for fdopendir on darwin/386

The INODE64 variant only exists on 64-bit.

Fixes #31262

Change-Id: I528277c9b3312fdb15463ccbea0d537ff300f4ae
Reviewed-on: https://go-review.googlesource.com/c/go/+/170837
Run-TryBot: Keith Randall <khr@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

src/syscall/syscall_darwin_386.go

@@ -70,7 +70,7 @@ func fdopendir(fd int) (dir uintptr, err error) {
 func libc_fdopendir_trampoline()
 
 //go:linkname libc_fdopendir libc_fdopendir
-//go:cgo_import_dynamic libc_fdopendir fdopendir$INODE64 "/usr/lib/libSystem.B.dylib"
+//go:cgo_import_dynamic libc_fdopendir fdopendir "/usr/lib/libSystem.B.dylib"
 
 // Implemented in the runtime package (runtime/sys_darwin_32.go)
 func syscall9(fn, a1, a2, a3, a4, a5, a6, a7, a8, a9 uintptr) (r1, r2 uintptr, err Errno)