JDK 14 RFR of JDK-8231545: Suppress warnings on non-serializable instance fields in jdk.jshell module

[Joe Darcy]

Hello,

Another part of the cleanup of library serialization usage ahead of 
augmented javac -Xlint warnings (JDK-8160675), the non-serializable 
instance fields of serializable types in the jdk.jshell module should 
have their serial warnings suppressed.

The analogous issue in core libs is JDK-8231202.

Patch below.

Thanks,

-Joe

diff -r e23e560afbcb 
src/jdk.jshell/share/classes/jdk/jshell/ExpressionToTypeInfo.java
--- a/src/jdk.jshell/share/classes/jdk/jshell/ExpressionToTypeInfo.java 
Wed Sep 25 21:26:38 2019 -0700
+++ b/src/jdk.jshell/share/classes/jdk/jshell/ExpressionToTypeInfo.java 
Thu Sep 26 10:43:05 2019 -0700
@@ -149,6 +149,7 @@
      private static class Result extends Error {

          static final long serialVersionUID = -5942088234594905629L;
+        @SuppressWarnings("serial") // Not statically typed as 
Serializable
          final TreePath expressionPath;

          Result(TreePath path) {