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
diff --git a/java/java.go b/java/java.go
index 51e8c34..2a4fafa 100644
--- a/java/java.go
+++ b/java/java.go
@@ -2258,11 +2258,11 @@
 				j.dexJarFileErr = err
 				return
 			}
-			dexJarFileApexRootRelative := apexRootRelativePathToJavaLib(j.BaseModuleName())
+			dexJarFileApexRootRelative := ApexRootRelativePathToJavaLib(j.BaseModuleName())
 			if dexOutputPath := di.PrebuiltExportPath(dexJarFileApexRootRelative); dexOutputPath != nil {
 				dexJarFile := makeDexJarPathFromPath(dexOutputPath)
 				j.dexJarFile = dexJarFile
-				installPath := android.PathForModuleInPartitionInstall(ctx, "apex", ai.ApexVariationName, apexRootRelativePathToJavaLib(j.BaseModuleName()))
+				installPath := android.PathForModuleInPartitionInstall(ctx, "apex", ai.ApexVariationName, ApexRootRelativePathToJavaLib(j.BaseModuleName()))
 				j.dexJarInstallFile = installPath
 
 				j.dexpreopter.installPath = j.dexpreopter.getInstallPath(ctx, installPath)
@@ -2422,7 +2422,7 @@
 // java_sdk_library_import with the specified base module name requires to be exported from a
 // prebuilt_apex/apex_set.
 func requiredFilesFromPrebuiltApexForImport(name string, d *dexpreopter) []string {
-	dexJarFileApexRootRelative := apexRootRelativePathToJavaLib(name)
+	dexJarFileApexRootRelative := ApexRootRelativePathToJavaLib(name)
 	// Add the dex implementation jar to the set of exported files.
 	files := []string{
 		dexJarFileApexRootRelative,
@@ -2433,9 +2433,9 @@
 	return files
 }
 
-// apexRootRelativePathToJavaLib returns the path, relative to the root of the apex's contents, for
+// ApexRootRelativePathToJavaLib returns the path, relative to the root of the apex's contents, for
 // the java library with the specified name.
-func apexRootRelativePathToJavaLib(name string) string {
+func ApexRootRelativePathToJavaLib(name string) string {
 	return filepath.Join("javalib", name+".jar")
 }