hg: jdk/jdk: 8225715: jhsdb jmap fails to write binary heap dump of a jshell process

[kevin.walls at oracle.com]

Changeset: f60890de1dfb
Author:    fmatte
Date:      2019-07-02 08:43 -0700
URL:       https://hg.openjdk.java.net/jdk/jdk/rev/f60890de1dfb

8225715: jhsdb jmap fails to write binary heap dump of a jshell process
Summary: Add a Null check for getSourceFileName() before writing into thread dump.
Reviewed-by: cjplummer, kevinw

! src/jdk.hotspot.agent/share/classes/sun/jvm/hotspot/utilities/HeapHprofBinWriter.java
+ test/jdk/sun/tools/jhsdb/JShellHeapDumpTest.java