bug#81211: #81211 31.0.90; Android build fails with current Java compilers

>
> In config.log, it says:
>
>   configure:7961: checking whether the Java compiler works
>   warning: [options] bootstrap class path not set in conjunction with
> -source 7
>   error: Source option 7 is no longer supported. Use 8 or later.
>   error: Target option 7 is no longer supported. Use 8 or later.
>   configure:7994: result: no


I managed to compile the Android version of Emacs with Java 11, which is an
LTS version, which happened to be the active version on my laptop.

configure:7861: checking whether the Java compiler works
warning: [options] bootstrap class path not set in conjunction with -source
7
1 warning
configure:7894: result: yes

So the solution is to use an older version of Java. Version 11 seems to
support "-source 7", version 21 does not. According to Google the last
version to support -source 7 is Java 19, which is not an LTS version, but
Java 17 is.