Add analyze_bcpf.py script to help manage bootclasspath_fragments

The analyze_bcpf.py script can be used by bootclasspath_fragment owners
to help setup their fragment and also to debug issues that arise during
use.

It is run by specifying the name of the bootclasspath_fragment module
in the --bcpf option. If specified the --apex and --sdk options will
allow the tool to produce more helpful messages.

The script currently:
* Builds out/soong/hiddenapi/hiddenapi-stub-flags.txt and checks any
  inconsistencies between those flags and the flags generated for the
  bootclasspath_fragment.

* Builds out/soong/hiddenapi/hiddenapi-flags.csv and checks any
  inconsistencies between those flags and the flags generated for the
  bootclasspath_fragment. It will describe the changes that need to
  be made in order to fix any inconsistencies in the flags.

Bug: 202154151
Test: m analyze_bcpf && analyze_bcpf --bcpf art-bootclasspath-fragment
      atest --host analyze_bcpf_test
Change-Id: I824fd9d527d246dfe56725c073d89a0b0e72d25a