Support for Android NDK r22

Support for Android NDK r22

This is a backport of #13434, Fixes #13685.

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: Tim Hudson <tjh@openssl.org>
Reviewed-by: Matt Caswell <matt@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/13694)