Fix -0 and argument type in ApplyUnsignedRoundingMode

Narrow the argument type of cmp to -1 | 0 | 1. The multiplication at one
of the call sites may additionally result in -0, so add +0 to neutralize
that.

Author: ptomato

lib/ecmascript.ts

@@ -4611,7 +4611,8 @@ export function RoundNumberToIncrementAsIfPositive(
   }
   // Similar to the comparison in RoundNumberToIncrement, but multiplied by an
   // extra sign to make sure we treat it as positive
-  const cmp = compare(abs(JSBI.multiply(remainder, TWO)), increment) * (JSBI.lessThan(quantity, ZERO) ? -1 : 1);
+  const cmp = (compare(abs(JSBI.multiply(remainder, TWO)), increment) * (JSBI.lessThan(quantity, ZERO) ? -1 : 1) +
+    0) as -1 | 0 | 1;
   const rounded = JSBI.equal(remainder, ZERO)
     ? quotient
     : ApplyUnsignedRoundingMode(r1, r2, cmp, isEven(r1), unsignedRoundingMode);

lib/math.ts

@@ -82,7 +82,7 @@ export function GetUnsignedRoundingMode(
 export function ApplyUnsignedRoundingMode<T extends number | JSBI>(
   r1: T,
   r2: T,
-  cmp: number,
+  cmp: -1 | 0 | 1,
   evenCardinality: boolean,
   unsignedRoundingMode: UnsignedRoundingMode
 ) {