Allow using updatable boot jars in dexpreopt (but don't use them yet).

This CL handles updatable boot jars in the same hacky way as we handle
non-updatable boot jars: it creates a set of predefined paths to the dex
jars in a global config, then traverses all modules in a singleton
context, finds updatable boot jars and adds copy rules from these jars
to the predefined paths. A proper way would be to register dependencies
of the dexpreopted modules on the boot jars and extracting paths to dex
files by walking these dependencies.

Bug: 178467404
Test: lunch aosp_cf_x86_64_phone-userdebug && m
Test: added new Soong test
Change-Id: I87f764109315f79315d73bf43799b70eb010fc0b

dexpreopt/config.go

@@ -33,6 +33,8 @@ type GlobalConfig struct {
 
 	OnlyPreoptBootImageAndSystemServer bool // only preopt jars in the boot image or system server
 
+	PreoptWithUpdatableBcp bool // If updatable boot jars are included in dexpreopt or not.
+
 	UseArtImage bool // use the art image (use other boot class path dex files without image)
 
 	HasSystemOther        bool     // store odex files that match PatternsOnSystemOther on the system_other partition