remove the "top of the comptime stack" compile error

It's still best practice to put `@setEvalBranchQuota` at the top of
the comptime stack, but as Jimmi notes in #1949, when a function
can be called at comptime and also can be the top of the comptime stack,
this compile error is fundamentally unsound.

So now it's gone.

closes #1949
c58b802034Andrew Kelley committed on 2/14/2019, 3:51:59 PMparenta4e32d9
2 files changedLine totals unavailable