[I'm laptop only so there's some chance this wi...

[I'm laptop only so there's some chance this will incur temporary
breakage, but it needs committing.]

Heading off gratuitous complications which haven't yet shipped, I
eliminated the -jar startup option in favor of doing what we already do,
figuring it out. So now all these things work.

  scala foo/bar.scala // if file is a script or has one main method
  scala foo.Bar // if it has a legal main method scala foo.jar // if it
  has a legal MainClass attribute

Also changed "-savecompiled" to "-save" and given scala source called
foo.scala, generate foo.jar rather than foo.scala.jar. Cleaned up a
bunch of related code and further polished the scala startup message.
And unbroke choice settings and improved that error too, which closes
#3849.

While trying to write a test for the choice setting, was reminded that
partest just discards invalid flags files. Made it fail instead, which
closes #3712. Fixed the new failures that revealed. No review.

1 files changed, 2 insertions, 0 deletions

diff --git a/test/files/neg/choices.check b/test/files/neg/choices.check
new file mode 100644
index 0000000000..3e63f9999d
--- /dev/null
+++ b/test/files/neg/choices.check
@@ -0,0 +1,2 @@
+partest error: bad flags: -Ylinearizer
+one error found