fix(runtime): Handle bigint mul/div within Number correctly (#1475)

Author: ospencer

compiler/test/stdlib/number.test.gr

@@ -54,6 +54,9 @@ assert Number.isNaN(Number.sub(Number.nan, Number.nan))
 }
 // mul
 assert Number.mul(5, 5) == 25
+assert Number.mul(9223372036854775809, 5) == 46116860184273879045
+assert Number.mul(9223372036854775809, 9223372036854775809) ==
+  85070591730234615884290395931651604481
 assert Number.mul(Number.infinity, 10) == Number.infinity
 assert Number.mul(Number.infinity, Number.infinity) == Number.infinity
 assert Number.isNaN(Number.mul(Number.infinity, Number.nan))
@@ -72,6 +75,8 @@ assert Number.isNaN(Number.mul(Number.nan, Number.nan))
 }
 // div
 assert Number.div(25, 5) == 5
+assert Number.div(9223372036854775809, 9) == 1024819115206086201
+assert Number.div(9223372036854775809, 9223372036854775809) == 1
 assert Number.div(Number.infinity, 10) == Number.infinity
 assert Number.isNaN(Number.div(Number.infinity, Number.infinity))
 assert Number.isNaN(Number.div(Number.infinity, Number.nan))

stdlib/runtime/numbers.gr

@@ -1424,6 +1424,13 @@ let numberTimesDivideBigIntHelp = (x, y, isDivide) => {
         Memory.decRef(yBig)
         ret
       },
+      t when WasmI32.eq(t, Tags._GRAIN_BIGINT_BOXED_NUM_TAG) => {
+        if (isDivide) {
+          reducedBigInteger(BI.div(x, y))
+        } else {
+          reducedBigInteger(BI.mul(x, y))
+        }
+      },
       t when WasmI32.eq(t, Tags._GRAIN_RATIONAL_BOXED_NUM_TAG) => {
         let yNumerator = boxedRationalNumerator(y)
         let yDenominator = boxedRationalDenominator(y)