Make scalac's argument-file processing more like javac's in handling spaces and line breaks

[som-snytt]

Fixes scala/bug#12732; the ticket has details on the behavior differences

[michelou]

@som-snytt Your changes work for me, thanks. I closed PR #10316 in favor of your PR after testing your changes with several Scala 2 code examples. I also patched the 2.13.10 installation (i.e. scala-compiler.jar) on my machines until version 2.13.11 is available.

[som-snytt]

@michelou Thanks for trying out the fix. I will probably not further tweak to be bug-compatible with Java.

To summarize, the change in 2.13.10 arrived in 2.13.9 but deemed too late in the cycle to refine, so it was reverted and deferred, but then did not receive further scrutiny; I see it got the "release notes" label, but only the -Vprint-args feature was highlighted.

I was hoping to use the same tokenizer for sys.process and arg files. That is a pipe dream. (sys.process pun.)

I'd forgotten this bug mentioned in my PR, which makes it sound like JDK has quoting bugs in both places:
https://bugs.openjdk.org/browse/JDK-8282008

The context is complicated by the reverts, but the original PRs were:
#10114
#10123

[SethTisue]

thanks @michelou for bringing this to our attention, and thanks @som-snytt for untangling the history

[SethTisue]

@som-snytt I improved the title and PR description a bit. not sure whether to put additional effort into it; on the one hand it's an incompatible change, so people need to know, but otoh I doubt the feature is widely used

[som-snytt]

@SethTisue yes, I think is really a reversion. If I could go back in time and live my life over again, this is what I would do differently.

I only work on features that nobody uses, so it should be safe.

[michelou]

@SethTisue Just one reminder to make sure this fix will go into release 2.13.11 : Kotlin and Scala 3 do behave the same as Java in respect to the handling of argument files passed on the command line.

PS. I make use of argument files in most build scripts (bash, batch, Makefile) available from my Github repositories (e.g. kotlin-examples, dotty-examples, akka-examples, etc..) when invoking the commands javac, kotlinc, and scalac (v3).