swift234

Enforce practical limits of _compiler_version

Internal compiler versions must be able to be packed into a 64-bit
value, and there is a limit on how many components we can use and which
values they can take on.

Versions must have no more than five components, assuming a version
X.Y.Z.a.b, where X, Y, Z, a, and b are integers with the following
inclusive ranges:

X: [0 - 214747]
Y: [0 - 999]
Z: [0 - 999]
a: [0 - 999]
b: [0 - 999]

Swift SVN r32724