Tune invocations and print full diagnostics on crash for d8 and r8.

Bug: 132766811
Test: treehugger
Change-Id: Id6943008e65b9dc3479e8758445e8d679529a8cb
diff --git a/java/config/config.go b/java/config/config.go
index 6ade649..d017ae6 100644
--- a/java/config/config.go
+++ b/java/config/config.go
@@ -52,7 +52,7 @@
 
 	pctx.StaticVariable("JavacHeapSize", "2048M")
 	pctx.StaticVariable("JavacHeapFlags", "-J-Xmx${JavacHeapSize}")
-	pctx.StaticVariable("DexFlags", "-JXX:+TieredCompilation -JXX:TieredStopAtLevel=1")
+	pctx.StaticVariable("DexFlags", "-JXX:OnError='cat hs_err_pid%p.log' -JXX:CICompilerCount=6 -JXX:+UseDynamicNumberOfGCThreads")
 
 	pctx.StaticVariable("CommonJdkFlags", strings.Join([]string{
 		`-Xmaxerrs 9999999`,