Add property to prevent dex preopting

Add dex_preopt property and pass it through to make as
LOCAL_DEX_PREOPT.

Test: m checkbuild
Change-Id: I6f19d097d1769068b7e4093f011574c540c137f3
diff --git a/java/androidmk.go b/java/androidmk.go
index e349de4..97924f3 100644
--- a/java/androidmk.go
+++ b/java/androidmk.go
@@ -36,6 +36,9 @@
 				}
 				if library.dexJarFile != nil {
 					fmt.Fprintln(w, "LOCAL_SOONG_DEX_JAR :=", library.dexJarFile.String())
+					if library.deviceProperties.Dex_preopt == nil || *library.deviceProperties.Dex_preopt == false {
+						fmt.Fprintln(w, "LOCAL_DEX_PREOPT := false")
+					}
 				}
 				fmt.Fprintln(w, "LOCAL_SDK_VERSION :=", library.deviceProperties.Sdk_version)
 			},