Function position refers to executor instead of command origin.

Summary:
Functions don't store the original position of their execution. They use the position of executor instead.

Example 1: Fixed by 1.10
(test.mcfunction)

execute @p ~ ~5 ~ function test2

(test2.mcfunction)

setblock ~ ~ ~ stone

Run /function test
Expected behavior:
Block is placed 5 blocks upward.
Actual behavior:
Block is placed at player's position. Relative coordinates are relative to the sender, when they should be relative to the execution position.

Example 2:
(test3.mcfunction)

tp @p ~ ~ ~5
setblock ~ ~ ~ stone

Run /function test3
Expected behavior:
Block is placed at original location function was called.
Actual behavior:
Block is placed at player's position after teleporting. The execution position was not updated using /execute, so it should have stayed put when the player was teleported.

How to reproduce:
1. Create functions described in the example above or apply the behaviorpack attached to this issue.
2. Call the functions with /function command to see the results.