Add min_sdk_version to Rust modules.

Add the min_sdk_version property to Rust modules so they can declare
a minimum SDK version they support for use with APEX modules.

Test: New Soong test passes.
Bug: 174862583
Change-Id: I2829053a320f50c218783dee5adbeff9cef81e8e
diff --git a/cc/testing.go b/cc/testing.go
index 95a93a0..3764fad 100644
--- a/cc/testing.go
+++ b/cc/testing.go
@@ -334,7 +334,7 @@
 			},
 			apex_available: [
 				"//apex_available:platform",
-				"myapex"
+				"//apex_available:anyapex",
 			],
 		}
 		cc_library {