Coverage: mark VarHandles as exempt from jacoco

The majority of methods here are compiler and/or runtime intrinsics
and so their invocations are not tracked by jacoco.

Bug: 203822478
Test: m -j EMMA_INSTRUMENT=true EMMA_INSTRUMENT_FRAMEWORK=true
Change-Id: I3d332375b8c41c9d905d7e6ad1424c252ce20db8
diff --git a/JavaLibrary.bp b/JavaLibrary.bp
index 24295f8..43fe7ba 100644
--- a/JavaLibrary.bp
+++ b/JavaLibrary.bp
@@ -279,6 +279,7 @@
             "java.lang.Object",
             "java.lang.String",
             "java.lang.invoke.MethodHandle",
+            "java.lang.invoke.VarHandle",
             "java.lang.ref.Reference",
             "java.lang.reflect.Proxy",
             "java.util.AbstractMap",