Batch mode debugger: print backtrace, quit with 1.

[c-kloukinas]

An attempt to resolve issue 750.

Now, when running in batch mode, an error causes a backtrace to be printed and abcl to exit with error code 1.

[c-kloukinas]

Before:

/usr/local/src$ java -server -Xrs -cp /usr/local/src/abcl/dist/abcl.jar org.armedbear.lisp.Main \
                       --noinform --batch --load not-there.lisp < /dev/null ; echo $?
#<THREAD "interpreter" native {58665DA1}>: Debugger invoked on condition of type FILE-ERROR
  File not found: /usr/local/src/not-there.lisp
[1] CL-USER(1): 0
/usr/local/src$

After:

/usr/local/src$ java -server -Xrs -cp /usr/local/src/abcl-chris/dist/abcl.jar org.armedbear.lisp.Main \
                       --noinform --batch --load not-there.lisp ; echo $?
#<THREAD "interpreter" native {2412ABF5}>: Debugger invoked on condition of type FILE-ERROR
  File not found: /usr/local/src/not-there.lisp

*** ERROR WHILE RUNNING IN BATCH MODE! ***
(#<LISP-STACK-FRAME (BACKTRACE) {6BDB4E03}> #<LISP-STACK-FRAME (INVOKE-DEBUGGER File not found: /usr/local/src/not-there.lisp) {43BEAC5D}> #<JAVA-STACK-FRAME org.armedbear.lisp.Lisp.error(Lisp.java:385) {89319F4}> #<JAVA-STACK-FRAME org.armedbear.lisp.Load.load(Load.java:165) {40284EA6}> #<JAVA-STACK-FRAME org.armedbear.lisp.Load.load(Load.java:124) {7132ABF6}> #<JAVA-STACK-FRAME org.armedbear.lisp.Interpreter.postprocessCommandLineArguments(Interpreter.java:333) {47D83DC9}> #<JAVA-STACK-FRAME org.armedbear.lisp.Interpreter.createDefaultInstance(Interpreter.java:110) {5794D07F}> #<JAVA-STACK-FRAME org.armedbear.lisp.Main$1.run(Main.java:46) {554BF955}> #<JAVA-STACK-FRAME java.base/java.lang.Thread.run(Thread.java:1583) {31C29511}>)
1
/usr/local/src$

(also note that we no longer need to do abcl ... < /dev/null )