Merge topic 'android-ndk-r19'

97bca2f9fa Android: Use unified toolchain in NDK r19+
19f36c5fb2 Android: Update test to not require GCC compiler to exist in NDK
f3e32ddae9 Android: Re-order system initialization to select sysroot last
9a0720b819 Android: Clarify name of internal variable for arch triple
4e6c58d937 Android: Select NDK host tag while determining system

Acked-by: Kitware Robot <kwrobot@kitware.com>
Merge-request: !3612