Updates jsilver to generate java8 bytecode.

Test: m jsilver. javap -p -v -cp out/host/linux-x86/framework/jsilver.jar  com/google/clearsilver/jsilver/values/StringValue | grep "major version" (outputs 52 instead of 53 now).

Bug: 170392930
Change-Id: Ia8e40364e7b6f8c2127c85009da71d3b91efb461
diff --git a/Android.bp b/Android.bp
index 169767d..4551ed4 100644
--- a/Android.bp
+++ b/Android.bp
@@ -13,6 +13,7 @@
 // limitations under the License.
 
 java_library_host {
+    java_version: "1.8",
     name: "jsilver",
     srcs: ["src/**/*.java"],
     libs: ["guava"],