…10709)

Fixes: #10705

When a \NativeAOT\ application starts up, certain portions of the managed startup
sequence are executed on the shared library load but before the \JNI_OnLoad\
function is invoked by Android.

Both \MonoVM\ and \CoreCLR\ hosts set environment variables which may affect the
way the application behaves before they initialize the managed runtime. Those
variables are set from within native code, using data generated at application
build time.

Until now, the \NativeAOT\ host followed suit, but it appears that we need to
set certain variables (e.g. those related to running the startup hooks) before
the shared library is loaded.

The only location where we can do it is the \NativeAndroidRuntimeProvider\ Java
class which is responsible for, eventually, loading the application shared
library.

This commit makes our build process emit application environment variables into
a Java file that's compiled together with the \NativeAndroidRuntimeProvider\
class, at the same time removing those variables from the native code so that
we don't set the variables twice (a performance optimization, nothing more).

Testing shows that startup hooks are properly called with only the \DOTNET_STARTUP_HOOKS\
variable set, which wasn't previously the case.

Co-authored-by: Jonathan Peppers <[email protected]>