Add better error handling to bootDexJar function

aosp/2876754 missed adding error handling to one of the places which
consumes the dex jar deapexed from prebuilt apexes. This CL ensures that
when we have multiple prebuilt apexes _without_ flagging, the hiddenapi
processing code emits a more descriptive error "Multiple deapxers..."
rather than a cryptic error "<module> does not provide a dex jar"

Test: m nothing --no-skip-soong-tests

Change-Id: I80849fa7cca17d724ac53c94bb353b169175ee28

java/java.go

@@ -2258,6 +2258,7 @@ func (j *Import) GenerateAndroidBuildActions(ctx android.ModuleContext) {
 				// An error was found, possibly due to multiple apexes in the tree that export this library
 				// Defer the error till a client tries to call DexJarBuildPath
 				j.dexJarFileErr = err
+				j.initHiddenAPIError(err)
 				return
 			}
 			dexJarFileApexRootRelative := ApexRootRelativePathToJavaLib(j.BaseModuleName())