Support PFor encoding

[Lloyd-Pottiger]

What problem does this PR solve?

Issue Number: ref #8789

Problem Summary:

What is changed and how it works?

PFor: patched frame of reference.

Format

| byte size | bit width | frame of reference | value[0] | ... | value[count]
   1 byte      1 byte         x bytes            b bits
   
x = byte size
b = bit width

Decompress

for i in [0, count]:
    value[i] = (frame_of_reference << b) + value[0]

Check List

Tests

• Unit test
• Integration test
• Manual test (add detailed scripts or steps below)
• No code

Side effects

• Performance regression: Consumes more CPU
• Performance regression: Consumes more Memory
• Breaking backward compatibility

Documentation

• Affects user behaviors
• Contains syntax changes
• Contains variable changes
• Contains experimental features
• Changes MySQL compatibility

Release note

None

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