Continue scalac compilation until just before bytecode generation

Previous behavior does not compile deep enough to surface errors.

See compiler phases:
https://docs.scala-lang.org/overviews/compiler-options/index.html#compilation-phases

ale_linters/scala/scalac.vim

@@ -9,7 +9,7 @@ endfunction
 call ale#linter#Define('scala', {
 \   'name': 'scalac',
 \   'executable_callback': {buf -> s:IsSbt(buf) ? '' : 'scalac'},
-\   'command': '%e -Ystop-after:parser %t',
+\   'command': '%e -Ystop-before:jvm %t',
 \   'callback': 'ale#handlers#scala#HandleScalacLintFormat',
 \   'output_stream': 'stderr',
 \})