switch from GDK_SCALE to J2D_UISCALE in netbeans launcher script for linux

### Description

Re: #7780

Conditions:
HiDPI, Linux, X11

When a program is developed in NB, that invokes a X program, the invoked program will inherit the GDK_SCALE environment variable, set by the netbeans launcher script. The effect will be 4x scaling in the invoked program.

Consider using J2D_UISCALE as a replacement for GDK_SCALE in the launcher script.

See also #7780 for a part of the discussion.

### Use case/motivation

To improve the fontscaling workaround used in launcher script.

### Related issues

#7780 #6185

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

Yes

Start by locating the NetBeans launcher script and review the HiDPI Linux/X11 behavior described here, then read related issues #7780 and #6185. Verify how the current GDK_SCALE setting is inherited by invoked X programs and confirm that the replacement avoids the unintended scaling while preserving NetBeans font scaling.

Written by the indexing model from the issue text.