Drop platform_apis from java_library

This property is a no-op for this module type.

Test: m nothing
Bug: 215379393
Change-Id: I0a94c4880f9af94e1a7bdac0476482394bed8135
diff --git a/experimental/experimental_api/Android.bp b/experimental/experimental_api/Android.bp
index 48b3573..5fe478d 100644
--- a/experimental/experimental_api/Android.bp
+++ b/experimental/experimental_api/Android.bp
@@ -31,5 +31,4 @@
 
     libs: ["android.car"],
 
-    platform_apis: true,
 }