Fix array literal slices with range operators

[fglock]

Problem

Array literal slices containing range operators like ('a','b','c','d','e','f')[0..5] were returning only the first element instead of the full slice.

Root Cause

The handleArrowArrayDeref method was using single-element optimization for all single-element array literal indices, but range operators need to be evaluated in LIST context to expand to multiple indices.

Solution

• Detect when an array literal slice contains a range operator in the indices
• Route such cases through the slice method instead of single-element optimization
• Target only true array literals (containing only StringNode/NumberNode elements) to avoid breaking existing functionality

Changes

• Modified src/main/java/org/perlonjava/codegen/Dereference.java to detect range operators in array literal indices
• Added logic to use slice method for array literals with range operators

Test Results

• ✅ Array literal slices with ranges now work: ('a','b','c','d','e','f')[0..5] returns 'abcdef'
• ✅ Tests 27 and 28 in op/array.t now pass
• ✅ Hash.t test count preserved: 26942 tests (no regression)
• ✅ All other array slice types continue to work correctly

Trade-offs

Expression slices like (@foo,@bar)[0..5] are not fixed by this change to avoid breaking hash.t functionality. Those would require a separate, more careful approach.