Use the correct prof file when multiple prebuilt apexes exist

Generating boot image requires a .prof file provided by the ART apex.
When building with prebuilts, this comes via the
prebuilt_bootclasspath_fragment module, which acts as a shim for
prebuilt_apex/apex_set. If we have multiple prebuilt apexes in the tree,
this shim becomes 1:many. This CL prepares dex_bootjars to select the
right .prof file when multiple prebuilts exist.

Implementation details
- Update deps mutator of dex_bootjars to create a dep on
  all_apex_contributions. The latter contains information about which
  apex is selected in a specific release configuration. dex_bootjars
  will create a dependency on the selected apex in a postdeps phase
  mutator.
- All apex module types (apex, prebuilt_apex and apex_set) will set a
  provider that contains info about the location of the .prof file on
  host
- dex_bootjars will access the provider of the selected apex to get the
  location of the .prof file

This CL does not drop the old mechanism to get the .prof file (i.e. by
creating a dep on {prebuilt_}bootclasspath_fragment). Once all mainline
modules have been flagged using apex_contributions, the old mechanism
will be dropped

Bug: 308790457
Test: Added a unit test that checks that the right .prof is selected
when multiple prebuilts exists

Change-Id: I40fdb21416c46bed32f6ff187ce5153711ec2c69