[Java] Fix BaseVariableWidthViewVector

[ViggoC]

Describe the bug, including details regarding any error messages, version, and platform.

Fix some bug in BaseVariableWidthViewVector

1. Fix handleSafe(), while (index >= getValueCapacity()) may goes into a dead loop until the validityBufferSize is overflow when dataLength == 0,
2. Fix copyFrom() and copyFromSafe(), the logic is wrong if fromIndex != thisIndex or the initialCapacity of the source and target vector is different.

Component(s)

Java

[vibhatha]

Could you please write the bug that you're trying to solve in the description?

[ViggoC]

@vibhatha The description is updated. Does it make sense to you?

[vibhatha]

Right, let me take look at the PR.