Support for Android NDK r22-beta1

Support for Android NDK r22-beta1

I think builds using standalone toolchain are fine so I left them alone,
but `Configure` will fail if using the NDK directly because the
`platforms` and `sysroot` directories were removed.

If `sysroot` is missing, omit the `--sysroot` and `-gcc-toolchain`
arguments and use the triplet form clang command.

Also since `platforms` was being used for the default API level, use
`meta/platforms.json` instead if needed.

Reviewed-by: Matt Caswell <matt@openssl.org>
Reviewed-by: Paul Dale <paul.dale@oracle.com>
Reviewed-by: Richard Levitte <levitte@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/13434)