bind/testdata: support JDK 8 for the reverse binding golden tests

The Character.Subset Java class changed between JDK 8 and JDK 11
which is the default JDK on my system. To avoid the golden tests
depend on the JDK version, drop the reference to the Character.Subset
class.
The inner class case is covered by the bind/java runtime tests.

For the upcoming Android container builders.

Change-Id: I05897ff7de7970633176207305099153de2f208c
Reviewed-on: https://go-review.googlesource.com/c/163377
Reviewed-by: Hyang-Ah Hana Kim <hyangah@gmail.com>

bind/testdata/java.go

@@ -6,7 +6,6 @@ package java
 
 import (
 	"Java/java/lang"
-	"Java/java/lang/Character"
 )
 
 type (
@@ -14,5 +13,4 @@ type (
 	L lang.Long
 	O lang.Object
 	R lang.Runnable
-	S Character.Subset // Inner class
 )