Add EMMA_INSTRUMENT_STATIC support

Add jacocoagent when instrumenting with EMMA_INSTRUMENT_STATIC.

Test: m EMMA_INSTRUMENT=true EMMA_INSTRUMENT_STATIC=true
Change-Id: I451bb9d16b7f0a66fd06c2da576062b28830e470
diff --git a/java/dex.go b/java/dex.go
index 2beb2ac..66e71b5 100644
--- a/java/dex.go
+++ b/java/dex.go
@@ -185,6 +185,11 @@
 		android.PathForSource(ctx, "build/make/core/proguard.flags"),
 	}
 
+	if j.shouldInstrumentStatic(ctx) {
+		flagFiles = append(flagFiles,
+			android.PathForSource(ctx, "build/make/core/proguard.jacoco.flags"))
+	}
+
 	flagFiles = append(flagFiles, j.extraProguardFlagFiles...)
 	// TODO(ccross): static android library proguard files