Remove shift type constraint

[tarakby]

Issue to be solved

When using shift operations, the shift value currently has to match the result type.

  // works
  let shift256: UInt256 = 240
  let result: UInt256 = 1 << shift256

  // errors
  let shift8: UInt8 = 240
  result = 1 << shift8

Although there is no harm in the current way, this is a constraint that the parser could remove since the values of shift are much smaller than the result of the operation.

Suggested Solution

For a backward compatible change, we can remove the condition for the shift value to be of the same type of the result. The shift value can be a positive integer of any size.

[bluesign]

The maximum value of shifts can be 255 since the largest type supported on Cadence is 256 bits.

Int can be bigger than 256 bits I guess.

[tarakby]

oh you're right @bluesign, I didn't know Int also supports shifts.
I updated the description, the suggested solution should remain the same.