[SPARK-44239][SQL][FOLLOWUP] Do not disable vector memory optimizatio…

…n when hugeVectorThreshold=0 to align its document

### What changes were proposed in this pull request?

Minor fix: Update default hugeVectorThreshold from 0 to -1 in code to match the documentation.
Keep consistent with the documentation

### Why are the changes needed?

Keep code and documentation consistent

### Does this PR introduce _any_ user-facing change?

No

### How was this patch tested?

Exists UT

### Was this patch authored or co-authored using generative AI tooling?

No

Closes #47988 from wankunde/minor_fix.

Authored-by: wankunde <[email protected]>
Signed-off-by: Kent Yao <[email protected]>

sql/core/src/main/java/org/apache/spark/sql/execution/vectorized/WritableColumnVector.java

@@ -72,7 +72,7 @@ public void reset() {
       numNulls = 0;
     }
 
-    if (hugeVectorThreshold > 0 && capacity > hugeVectorThreshold) {
+    if (hugeVectorThreshold > -1 && capacity > hugeVectorThreshold) {
       capacity = defaultCapacity;
       releaseMemory();
       reserveInternal(capacity);