Make D8 Desugaring default.

Bug: 69329508
Test: m checkbuild

Change-Id: Ie74c2b27764aa5f2d60a0d33141735808bbc6d48
diff --git a/android/config.go b/android/config.go
index 2ed6413..630785b 100644
--- a/android/config.go
+++ b/android/config.go
@@ -588,7 +588,7 @@
 }
 
 func (c *config) UseD8Desugar() bool {
-	return c.IsEnvTrue("USE_D8_DESUGAR")
+	return !c.IsEnvFalse("USE_D8_DESUGAR")
 }
 
 func (c *config) UseGoma() bool {