Remove special case code for obsolete files

incompatibilities.txt doesn't exist anymore, only
"<module>-incompatibilities.txt". Clean up the associated logic that
mapped incompatibilities.txt to android-incompatibilities.txt.

Bug: 178171189
Test: m
Change-Id: I61eeb5dcc82770fa2af356bad11b7205551d6d83
diff --git a/java/prebuilt_apis.go b/java/prebuilt_apis.go
index 8a442b5..c33e6c2 100644
--- a/java/prebuilt_apis.go
+++ b/java/prebuilt_apis.go
@@ -253,14 +253,8 @@
 		files := getPrebuiltFilesInSubdir(mctx, nextApiDir, "api/*incompatibilities.txt")
 		for _, f := range files {
 			localPath := strings.TrimPrefix(f, mydir)
-			module, _, scope := parseApiFilePath(mctx, localPath)
-
-			// Figure out which module is referenced by this file. Special case for "android".
-			referencedModule := strings.TrimSuffix(module, "incompatibilities")
-			referencedModule = strings.TrimSuffix(referencedModule, "-")
-			if referencedModule == "" {
-				referencedModule = "android"
-			}
+			filename, _, scope := parseApiFilePath(mctx, localPath)
+			referencedModule := strings.TrimSuffix(filename, "-incompatibilities")
 
 			createApiModule(mctx, apiModuleName(referencedModule+"-incompatibilities", scope, "latest"), localPath)