Revert "[runtime] Remove a bit chunk of what's dead code now."

This reverts commit cab1c00168a773bd75ea3bee155dca12e88c9b78.
Revert "[runtime] Implement lazy resolution of array interfaces."

This reverts commit 6ee08cf772eb95c59ea81270523b210cb5948bc1.

This broke corlib compilation in a very weird way. Reverting it for now as I have no idea on why things break.