Use the correct bootjars when multiple prebuilt apexes exist

hiddenapi and dexpreopt require boot and system server jars from apexes.
When building with prebuilts, this comes via
java_import/java_sdk_library_import, which acts as a hook for
prebuilt_apex/apex_set. If we have multiple apexes in the tree, this
hook becomes 1:many. This CL prepares dex_bootjars to select the right
deapexerd .jar files when mutliple prebuilts exist.

Implementation details
- Update prebuilt module types (prebuilt_apex/apex_set) and source
  apexes to set a map of
  library name to dex jar path on host.
- dex_bootjars will access the path of the .dex jar on host via the
  provider. These then
  copied/installed to the right locations.

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

Bug: 308790457
Test: git_master-art-host:art-gtest https://android-build.corp.google.com/builds/abtd/run/L21500030000926533
Test: git_main:art_standalone_dexpreopt_tests https://android-build.corp.google.com/builds/abtd/run/L99000030000891212
Test: Added a unit test that checks that the right .jar is selected
when multiple prebuilts exists

Change-Id: I6ef94135b9303a35135810930af4b641df13a583

java/hiddenapi_modular.go

@@ -947,6 +947,7 @@ type HiddenAPIOutput struct {
 	HiddenAPIFlagOutput
 
 	// The map from base module name to the path to the encoded boot dex file.
+	// This field is not available in prebuilt apexes
 	EncodedBootDexFilesByModule bootDexJarByModule
 }