Automatically set compile_dex:true and hostdex:true for APEX variants

... unless they are turned off explicitly.

Bug: 147221965
Test: m
Change-Id: I6b91d6409d9cf06ad09467c53d5d51a9c693256e
diff --git a/apex/apex_test.go b/apex/apex_test.go
index 508bde6..9152fdd 100644
--- a/apex/apex_test.go
+++ b/apex/apex_test.go
@@ -453,7 +453,6 @@
 			srcs: ["foo/bar/MyClass.java"],
 			sdk_version: "none",
 			system_modules: "none",
-			compile_dex: true,
 			static_libs: ["myotherjar"],
 			libs: ["mysharedjar"],
 			// TODO: remove //apex_available:platform
@@ -468,7 +467,6 @@
 			srcs: ["foo/bar/MyClass.java"],
 			sdk_version: "none",
 			system_modules: "none",
-			compile_dex: true,
 			// TODO: remove //apex_available:platform
 			apex_available: [
 				"//apex_available:platform",
@@ -481,7 +479,6 @@
 			srcs: ["foo/bar/MyClass.java"],
 			sdk_version: "none",
 			system_modules: "none",
-			compile_dex: true,
 		}
 	`)
 
@@ -594,7 +591,6 @@
 			srcs: ["foo/bar/MyClass.java"],
 			sdk_version: "none",
 			system_modules: "none",
-			compile_dex: true,
 			apex_available: [ "myapex" ],
 		}
 
@@ -2987,7 +2983,6 @@
 			srcs: ["foo/bar/MyClass.java"],
 			sdk_version: "none",
 			system_modules: "none",
-			compile_dex: true,
 			enabled: false,
 		}
 	`)
@@ -3518,7 +3513,6 @@
 			srcs: ["foo/bar/MyClass.java"],
 			sdk_version: "none",
 			system_modules: "none",
-			compile_dex: true,
 			apex_available: [ "myapex" ],
 		}
 	`)
@@ -3547,6 +3541,7 @@
 			srcs: ["foo/bar/MyClass.java"],
 			sdk_version: "none",
 			system_modules: "none",
+			compile_dex: false,
 		}
 	`)
 }
@@ -3633,7 +3628,6 @@
 			sdk_version: "none",
 			system_modules: "none",
 			libs: ["myotherjar"],
-			compile_dex: true,
 			apex_available: [
 				"myapex",
 				"//apex_available:platform",