Test coc-java with genearted code

to reproduce the problem, run (on mac m1):

1. ./mvnw -Dos.detected.classifier=osx-x86_64 compile
2. tree target/generated-sources/protobuf/ should see generated source
3. comment out "java.autobuild.enabled": false (default to true)
4. open ./src/main/java/io/grpc/examples/helloworld/service/GreeterImpl.java and project should build automatcially and this file will show error
5. tree target/generated-sources/protobuf/ should see generated source gone
6. repeate 1-6 but skip 3, you shouldn't see any errors

Observations:

It seems building manaually doesn't trigger this problem(full or incremental). The LSP issued was

[Trace - 16:56:34] Sending request 'java/buildWorkspace - (6)'.
Params: [
 true
]

Init workspace will clean out the source code by default.

The java.autobuild.enabled will set the initializationOptions.settings.java.autobuild.enabled to false, which disables initial workspace build, and in turn won't clean our generated sources

You can check by inspecting java.output