WW-5646 Modernize path normalization in Include component

[arunmanni-ai]

The path normalization logic in Include.getContextRelativePath() used the
legacy java.util.Stack class and did not handle the edge case where
dot-dot segments exceed the available path depth.

This patch:

• Replaces java.util.Stack with ArrayDeque (recommended since JDK 6)
• Adds an isEmpty() guard before pop() to handle excess dot-dot gracefully
• Uses enhanced for-loop instead of indexed elementAt() iteration
• Adds test coverage for edge case dot-dot paths