Close gaps in generate features dev mode flow integration tests

[kathrynkodama]

Generate features is currently enabled for all of the dev mode integration tests, see
ci.maven: #1368 and #1370
ci.gradle: OpenLiberty/ci.gradle#689 and OpenLiberty/ci.gradle#692

We need to add assert statements to verify that generate features is running at the correct time in the dev mode flow:

• Generate features is running on dev mode startup
• Generate features is running after a Java change and is generating the correct new features
• Generate features does not run if there are compilation errors
• "o" and Enter to optimize features
• Toggling feature generation on/off with "g" hotkey
• All of the above for multi module Maven projects (Kathryn to investigate)

The following cases may depend on #1389

• Generate features runs after build file change (Kathryn)
  • ci.gradle has a bug when trying to edit a build.gradle file in an integration test: Add dev mode integration tests for build.gradle changes ci.gradle#708
  • added to ci.maven as part of Feature generation and dev mode, build file modified integration test fix #1409
• Generate features runs after config file change (xml file with features block is modified) https://github.com/OpenLiberty/ci.maven/pull/1445/files Generate features when features list has been modified, triggered from config file change ci.gradle#720
• Generate features runs on restart, "r" + Enter (Paul)
• Consider scenarios where generate features fails (ie. ensure that install features does not run, the dev mode flow continues, etc)
• Optimize generate features runs after server.xml changes. Specifically test for feature removal. If feature(s) are removed from server.xml that are needed, they should be generated. (Trevor)