Slow background indexing

### Apache NetBeans version

Apache NetBeans 27

### What happened

While working on PHP project the mouse cursor alternates between the timeout icon and the normal icon for a long time, rapidly switching between the two icons.

After investigation we noticed big difference in times of background scanning.

For example in Netbeans 26 message.log contains following messages:
INFO [org.netbeans.ui.indexing]: Indexing started, time from last indexing 143 888 ms.
INFO [org.netbeans.ui.indexing]: Indexing finished, indexing took 432 ms.
INFO [org.netbeans.ui.indexing]: Indexing started, time from last indexing 61 205 ms.
INFO [org.netbeans.ui.indexing]: Indexing finished, indexing took 379 ms.
INFO [org.netbeans.ui.indexing]: Indexing started, time from last indexing 29 079 ms.
INFO [org.netbeans.ui.indexing]: Indexing finished, indexing took 468 ms.

While for Netbeans 27 message log contain following:
INFO [org.netbeans.ui.indexing]: Indexing started, time from last indexing 27 846 ms.
INFO [org.netbeans.ui.indexing]: Indexing finished, indexing took 1 343 ms.
INFO [org.netbeans.ui.indexing]: Indexing started, time from last indexing 187 382 ms.
INFO [org.netbeans.ui.indexing]: Indexing finished, indexing took 7 073 ms.
INFO [org.netbeans.ui.indexing]: Indexing started, time from last indexing 184 393 ms.
INFO [org.netbeans.ui.indexing]: Indexing finished, indexing took 9 249 ms.

### Language / Project Type / NetBeans Component

PHP

### How to reproduce

Open big PHP project on CIFS/Samba network drive.

### Did this work correctly in an earlier version?

Apache NetBeans 26

### Operating System

Windows 11

### JDK

JDK 24

### Apache NetBeans packaging

FoAN provided installer

### Anything else

_No response_

### Are you willing to submit a pull request?

No

No source file or test is named; start at the background indexing entry point and reproduce the comparison using a large PHP project on a CIFS/Samba drive under Windows 11. Compare the NetBeans 26 and 27 indexing logs, and consider the issue done when indexing no longer shows the reported slowdown and cursor disruption.

Written by the indexing model from the issue text.