Widen volumeHandle to long before shifting by 48 (CodeQL java/lshift-larger-than-type-width)

[vharseko]

Summary

Resolves the single java/lshift-larger-than-type-width CodeQL alert in
IOMeter.java.

IOMeter.dump() builds a composite key that groups journal events by
(volumeHandle, pageAddress):

final int volumeHandle = is.readInt();
final long pageAddress = is.readLong();
...
final long handle = (volumeHandle << 48) + pageAddress;   // bug

volumeHandle is an int, and Java masks an int shift distance to its low
5 bits, so << 48 is actually evaluated as << (48 & 31) = << 16 in 32-bit
arithmetic and only then widened to long. As a result:

• the volume handle lands in bits 16–47 instead of 48+, and
• volumeHandle << 16 can overflow int,

so events for different volumes/pages can collide on the same HashMap key.

Fix

Cast to long before the shift so it is performed in 64 bits:

final long handle = ((long) volumeHandle << 48) + pageAddress;

This only affects the -a (analyze pages) mode of the journal-dump diagnostic
utility; it is not on a data path.

Testing

mvn -o -pl persistit/core -am compile — BUILD SUCCESS.