Fix build for boot2qt eAndroid

Reverts the removal of Android support in WTF, and brings the support
up to date.

Merged change to MacroAssemblerARM.cpp from QtScript.

Replaces use of statvfs with statfs in one place.

Replaces shm-based shared memory with ashmem-based in WebKit2.

Change-Id: I440b1fbd94bb4148f7ba764d77de65230d13ed90
Reviewed-by: Simon Hausmann <simon.hausmann@digia.com>