Update min_sdk_version from SdkSpec to ApiLevel

This relands aosp/2457063. The original change broke T and U since those
branches still contain soong modules of type (kind+level). Those soong
modules have been cleaned up now

Test: Used go/abtd to test T and U branches with this change

Bug: 208456999
Change-Id: I0ef7933c055f88cb512a02108f1173e51156ef1c
diff --git a/java/classpath_fragment.go b/java/classpath_fragment.go
index cf81ddb..45e6175 100644
--- a/java/classpath_fragment.go
+++ b/java/classpath_fragment.go
@@ -130,13 +130,13 @@
 				if s, ok := m.(*SdkLibrary); ok {
 					// TODO(208456999): instead of mapping "current" to latest, min_sdk_version should never be set to "current"
 					if s.minSdkVersion.Specified() {
-						if s.minSdkVersion.ApiLevel.IsCurrent() {
+						if s.minSdkVersion.IsCurrent() {
 							jar.minSdkVersion = ctx.Config().DefaultAppTargetSdk(ctx).String()
 						} else {
-							jar.minSdkVersion = s.minSdkVersion.ApiLevel.String()
+							jar.minSdkVersion = s.minSdkVersion.String()
 						}
 					}
-					if s.maxSdkVersion.Specified() {
+					if s.maxSdkVersion.ApiLevel.Specified() {
 						if s.maxSdkVersion.ApiLevel.IsCurrent() {
 							jar.maxSdkVersion = ctx.Config().DefaultAppTargetSdk(ctx).String()
 						} else {