Clang 10's -Wimplicit-int-float-conversion complains that
MAX = 2147483647 cannot be exactly represented as a float.

Use an explicit conversion to suppress the warning locally. Note that
this value's usage to produce a random boolean doesn't critically depend
on exact conversion.

Bug: b/152777669
Change-Id: I1136ca16dcb842b97f4a76a6ed3e1c3333e814f8
Reviewed-on: https://swiftshader-review.googlesource.com/c/SwiftShader/+/51488Tested-by: Nicolas Capens <nicolascapens@google.com>
Commit-Queue: Nicolas Capens <nicolascapens@google.com>
Kokoro-Result: kokoro <noreply+kokoro@google.com>
Reviewed-by: Antonio Maiorano <amaiorano@google.com>