Deprecate Snapshot build

Existing snapshot code will no longer work from VNDK deprecation, but it
can give confusion to users if we keep code for the snapshot - and it
adds complexity on existing code while it is not in use. This change
removes all snapshot definition except host snapshot and its usage.

Bug: 330100430
Bug: 332986564
Test: AOSP CF build succeeded
Change-Id: Ieb6fa43d5e38315c662ce997bc305b744b367c24

cc/sdk.go

@@ -106,8 +106,6 @@ func sdkMutator(ctx android.BottomUpMutatorContext) {
 			}
 			ctx.AliasVariation("")
 		}
-	case *snapshotModule:
-		ctx.CreateVariations("")
 	case *CcApiVariant:
 		ccApiVariant, _ := ctx.Module().(*CcApiVariant)
 		if String(ccApiVariant.properties.Variant) == "ndk" {