add aidl.export_include_dirs to java_import module type

This allows a java prebuilt to export AIDL files to its clients.

Bug: 151933053
Test: m
Change-Id: I21b5d5ce647141a7c76f62490adbccb858b10323

java/testing.go

@@ -50,6 +50,8 @@ func TestConfig(buildDir string, env map[string]string, bp string, fs map[string
 		"api/test-current.txt":   nil,
 		"api/test-removed.txt":   nil,
 		"framework/aidl/a.aidl":  nil,
+		"aidl/foo/IFoo.aidl":     nil,
+		"aidl/bar/IBar.aidl":     nil,
 		"assets_a/a":             nil,
 		"assets_b/b":             nil,