Tile Streamed in Temporarily has Stepping on Landscape

This was reported in a UDN.

Jeremy M. originally pointed out that the stepping looks to be caused by high res geometry sampling a low res heightmap.

Additional observations:

• Loading the tile in with visibility disabled and then enabling it x amount of time after still produced the bug.
• The amount of time varied. Saw huge improvement when enabling the Landscape stat.

• Create a main level and a level with a non-flat Landscape.

• • A heightmap liked this worked:
    • Section size: 63x63 
    • Sections per component: 1x1 
    • Num of components: 9x9
• Enable world composition.
• Put the landscape level in a layer without distance streaming.
• Unload the landscape level.
• Stream the landscape tile in using BP during PIE.