tls: update source, related test & doc for ArrayBuffer/DataView

Refs: #1826 (closed)

Referring to the comment in "mentor-available" #1826, this PR tries out the tls item from the checklist of the comment: (Thanks for your review!)

• use isArrayBufferView in place of isUint8Array
• update test code in "test-tls-basic-validations.js"
• update tls.md doc.

• make -j4 test (UNIX), or vcbuild test (Windows) passes
• tests and/or benchmarks are included
• documentation is changed or added
• commit message follows commit guidelines