OOME when opening CPU samples in JFR

[pflaska]

Describe the bug
A clear and concise description of what the bug is.

To Reproduce
Steps:

1. Load a JFR file (My JFR is ~250MB).
2. Switch to Samper
3. Click the CPU button to get CPU samples
4. Error in console.

Current behavior:

java.lang.OutOfMemoryError: Java heap space
Dumping heap to /home/pflaska/.visualvm/2.1.10/var/log/heapdump.hprof ...

Exception: java.lang.OutOfMemoryError thrown from the UncaughtExceptionHandler in thread "AWT-XAWT"
Heap dump file created [1504753334 bytes in 7,055 secs]

Expected behavior

The JFR is not huge, VisualVM should be able to open it.

** Workaround**
Increasing -Xmx to 8GB works.

Desktop (please complete the following information):

• Ubuntu 22.04.5 LTS \n \l
• Java(TM) SE Runtime Environment 17-ea+15-LTS-1230
• 2.1.10

[thurka]

Memory usage improved. With the above fix I was able to open test jfr file with 1500M Xmx, while originaly VisualVM needs around 6G.