Improve date binding compatibility

std/assembly/bindings/Date.ts

@@ -1,10 +1,12 @@
 export declare function UTC(
+  // NOTE: Using i32 below saves us a f64.convert_s instruction and moves the responsibility for
+  // converting the value to the WASM/JS boundary.
   year: i32,
   month: i32,
   day: i32,
   hour: i32,
   minute: i32,
   second: i32,
-  millisecond: i32
+  millisecond: f64
 ): f64;
 export declare function now(): f64;

std/assembly/date.ts

@@ -12,9 +12,9 @@ export class Date {
     hour: i32 = 0,
     minute: i32 = 0,
     second: i32 = 0,
-    millisecond: i32 = 0
+    millisecond: i64 = 0
   ): i64 {
-    return <i64>Date_UTC(year, month, day, hour, minute, second, millisecond);
+    return <i64>Date_UTC(year, month, day, hour, minute, second, <f64>millisecond);
   }
 
   @inline static now(): i64 {
@@ -31,7 +31,8 @@ export class Date {
     return this.value;
   }
 
-  setTime(value: i64): void {
+  setTime(value: i64): i64 {
     this.value = value;
+    return value;
   }
 }

std/assembly/index.d.ts

@@ -675,7 +675,7 @@ declare class Date {
   /** Returns the UTC timestamp of this date in milliseconds. */
   getTime(): i64;
   /** Sets the UTC timestamp of this date in milliseconds. */
-  setTime(value: i64): void;
+  setTime(value: i64): i64;
 }
 
 /** Environmental tracing function for debugging purposes. */

std/portable/index.d.ts

@@ -442,7 +442,7 @@ declare class Date {
   /** Returns the UTC timestamp of this date in milliseconds. */
   getTime(): number;
   /** Sets the UTC timestamp of this date in milliseconds. */
-  setTime(value: number): void;
+  setTime(value: number): number;
 }
 
 declare namespace console {