aconfig: add Java integration tests

Add integration tests for Java. This test setup verifies that

  - the build system calls aconfig to generate a Java library
  - the Java test compiles against the auto-generated library
  - the auto-generated code returns expected values

Similar integration tests for C++ and Rust will be added in follow-up
CLs.

Note: the build does not currently support specifying that
tests/*.values should be applied, so the test flags will all be assigned
the defaults. A later CL will fix this.

Bug: b/283911467
Test: atest aconfig.test aconfig.test.java
Change-Id: Ia365e209261f4935a23e2dac9ef0ab5b60f76e52

tools/aconfig/src/codegen_java.rs

@@ -59,7 +59,7 @@ fn create_class_element(package: &str, item: &Item) -> ClassElement {
     let device_config_flag = codegen::create_device_config_ident(package, &item.name)
         .expect("values checked at cache creation time");
     ClassElement {
-        method_name: item.name.clone(),
+        method_name: item.name.replace('-', "_"),
         readwrite: item.permission == Permission::ReadWrite,
         default_value: if item.state == FlagState::Enabled {
             "true".to_string()