[Mesa-stable] isl support for Android (final version)

[Mauro Rossi]

As agreed with Emil, I'm sending a respin of isl for Android,
without python3 macro definition in main Android.mk, since not needed anymore,
and with a few optimizations in makefiles.

In order to backport to mesa-stable the patches, which is recommended,
the patches that remove python3 features from isl are a pre-requisite.

Cc: <mesa-stable at lists.freedesktop.org>