This makes MockUniform fail if the action is specified to return an out of bounds value.

Examples that will fail:

  absl::Uniform(gen, 1, 4) -> 42
  absl::Uniform(gen, 1, 4) -> 4: [1, 4)
  absl::Uniform(absl::IntervalOpenClosed, gen, 1, 4) -> 1: (1, 4]

Examples that will pass:

  absl::Uniform(gen, 1, 4) -> 3
  absl::Uniform(gen, 1, 4) -> 1: [1, 4)
  absl::Uniform(absl::IntervalClosed, gen, 1, 4) -> 4: [1, 4]

Special case: the empty range always returns its boundary, so this case passes:

  absl::Uniform(absl::IntervalOpen, 1, 1) -> 1: (1, 1)

If this breaks your test, your test has a bug: it's relying on an absl::Uniform() call that returns an impossible value. The UnvalidatedMockingBitGen type temporarily exists to allow for disabling the validation to give a bit of time to fix the test, but this type will go away soon.

PiperOrigin-RevId: 643090275
Change-Id: I23470fa9e1efbcb42fa3866237038414545c7be2