Print further details on an AbruptExitException.

Otherwise we just get a trivial message with the summary of the exception
that caused the failure... but zero context even if it exists.  This is a
requirement to get useful information when we fail hard.  Dumping a stack
trace may not be the nicest for the user, but given that this is improving
a catch-all location, I'd rather get more information than nothing.  If we
need to print more succinct messages in other circumstances, we can
special-case those.

While here, also add missing trailing newlines to a few messages that need
them.

RELNOTES: None.
PiperOrigin-RevId: 210409135

src/main/java/com/google/devtools/build/lib/runtime/BlazeRuntime.java

diff --git a/src/main/java/com/google/devtools/build/lib/runtime/BlazeRuntime.java b/src/main/java/com/google/devtools/build/lib/runtime/BlazeRuntime.java
index a9df409..57dc16f 100644
--- a/src/main/java/com/google/devtools/build/lib/runtime/BlazeRuntime.java
+++ b/src/main/java/com/google/devtools/build/lib/runtime/BlazeRuntime.java
@@ -93,6 +93,7 @@
 import java.io.File;
 import java.io.IOException;
 import java.io.OutputStream;
+import java.io.PrintStream;
 import java.lang.reflect.Type;
 import java.nio.charset.StandardCharsets;
 import java.time.Duration;
@@ -951,13 +952,14 @@
       dispatcher.shutdown();
       return ExitCode.SUCCESS.getNumericExitCode();
     } catch (OptionsParsingException e) {
-      outErr.printErr(e.getMessage());
+      outErr.printErrLn(e.getMessage());
       return ExitCode.COMMAND_LINE_ERROR.getNumericExitCode();
     } catch (IOException e) {
-      outErr.printErr("I/O Error: " + e.getMessage());
+      outErr.printErrLn("I/O Error: " + e.getMessage());
       return ExitCode.BUILD_FAILURE.getNumericExitCode();
     } catch (AbruptExitException e) {
-      outErr.printErr(e.getMessage());
+      outErr.printErrLn(e.getMessage());
+      e.printStackTrace(new PrintStream(outErr.getErrorStream(), true));
       return e.getExitCode().getNumericExitCode();
     } finally {
       if (sigintHandler != null) {