Add an extra argument `os_file_handle file` for `os_mmap` to support
mapping file from a file fd, and remove `os_get_invalid_handle` from
`posix_file.c` and `win_file.c`, instead, add it in the `platform_internal.h`
files to remove the dependency on libc-wasi.
Signed-off-by: Huang Qi <huangqi3@xiaomi.com>