Convert more versions in config to ApiLevel.

The test case I removed is invalid. The codename has had its int
assigned, but the config claims it is not final.

If this ever does need to be supported it's just a matter of making
sure the Q -> 29 mapping (or whatever) in the finalized codenames map
in android/api_levels.go.

Test: treehugger
Bug: http://b/154667674
Change-Id: I4f42ec2fd4a37750519ee3937938a1c65b6bb1e8
diff --git a/java/aar.go b/java/aar.go
index fcdd9c3..9cab0bd 100644
--- a/java/aar.go
+++ b/java/aar.go
@@ -189,7 +189,7 @@
 
 	// Version code
 	if !hasVersionCode {
-		linkFlags = append(linkFlags, "--version-code", ctx.Config().PlatformSdkVersion())
+		linkFlags = append(linkFlags, "--version-code", ctx.Config().PlatformSdkVersion().String())
 	}
 
 	if !hasVersionName {