fix: startup warning if _JAVA_OPTIONS is set

[Vinfall]

I have _JAVA_OPTIONS set in my environment and this is causing problem when checking Java versions. This PR solves the issue by filtering out this info in java -version output.

# .profile
export _JAVA_OPTIONS="-Djavafx.cachedir=$XDG_CACHE_HOME/openjfx"

With above settings, the output is problematic even if you use sed:

$ java -version
Picked up _JAVA_OPTIONS: -Djavafx.cachedir=/home/user/.cache/openjfx
openjdk version "21.0.6" 2025-01-21
OpenJDK Runtime Environment (build 21.0.6+1-void-r1)
OpenJDK 64-Bit Server VM (build 21.0.6+1-void-r1, mixed mode, sharing)

Warning message (the program itself runs fine though):

$ cd blahblah/to/ffdec
$ ./ffdec.sh
./ffdec.sh: line 47: [: Picked up _JAVA_OPTIONS: -Djavafx.cachedir=/home/user/.cache/openjfx 21: integer expression expected
./ffdec.sh: line 49: [: Picked up _JAVA_OPTIONS: -Djavafx.cachedir=/home/user/.cache/openjfx 21: integer expression expected
./ffdec.sh: line 53: [: Picked up _JAVA_OPTIONS: -Djavafx.cachedir=/home/user/.cache/openjfx 0: integer expression expected
./ffdec.sh: line 55: [: Picked up _JAVA_OPTIONS: -Djavafx.cachedir=/home/user/.cache/openjfx 0: integer expression expected
./ffdec.sh: line 59: [: Picked up _JAVA_OPTIONS: -Djavafx.cachedir=/home/user/.cache/openjfx 6: integer expression expected
./ffdec.sh: line 61: [: Picked up _JAVA_OPTIONS: -Djavafx.cachedir=/home/user/.cache/openjfx 6: integer expression expected
./ffdec.sh: line 65: [: Picked up _JAVA_OPTIONS: -Djavafx.cachedir=/home/user/.cache/openjfx : integer expression expected
Picked up _JAVA_OPTIONS: -Djavafx.cachedir=/home/user/.cache/openjfx

Only tested on Void Linux with OpenJDK21 installed.

[jindrapetrik]

Thank you.