ndk_library: separate abidw and abitidy into separate rules

Both processes might consume a large amount of memory when analyzing
library ABIs. By chaining them via a pipe we keep the same
representation twice in memory. That can introduce a problematic peak
memory consumption. Hence, split them apart into separate rules that
depend on each other.

Bug: 191235788
Test: m out/soong/abi-dumps/ndk/28/x86_64/libc/abi.xml
Signed-off-by: Matthias Maennich <maennich@google.com>
Change-Id: Ia0264a5ede5b2c2a3c2e3fbe968c11d36acf33c2