ui: Small {heap,java}prof cleanup in record_controller
ui: Small {heap,java}prof cleanup in record_controller

- Remove some ! asserts
- Extract a few variables so stuff fits on one line
- Better handle empty lines
- Rename 'theJavaHprof'
- Avoid a ternary

Change-Id: I34fe91e2dc0e9bcab38978a5fda65c779148b5c6
google/perfetto,google/perfetto,google/perfetto,google/perfetto,google/perfetto,google/perfetto,google/perfetto,google/perfetto