Allow mixin constructor have parameters before rest parameter

## Search Terms mixin, constructor parameters ## Suggestion Allow mixin constructor have parameters before rest parameter and infer the combination between mixin parameters. ## Use Cases The following js code is completely valid and functional. However with the actual mixin constructor constraints we can't reproduce this in Typescript. ```js const mixin1 = (base) => class Mixin1 extends base { constructor(m1v1, m1v2, ...args) { super(...args); this.m1v1 = m1v1; this.m1v2 = m1v2; } }; const mixin2 = (base) => class Mixin2 extends base { constructor(m2v1, m2v2, ...args) { super(...args); this.m2v1 = m2v1; this.m2v2 = m2v2; } }; class Base { constructor(v1, v2) { this.v1 = v1; this.v2 = v2; } } class C1 extends mixin1(Base) { } class C2 extends mixin2(Base) { } class C3 extends mixin2(mixin1(Base)) { } console.log(new C1("m1v1", true, 1, {})); console.log(new C2(false, 2, 1, {})); console.log(new C3(false, 2, "m1v1", true, 1, {})); ``` ## Examples Same code expected work in ts with constructor inference. ```ts type Constructor = new (...args: any[]) => object; const mixin1 = <T extends Constructor>(base: T) => class Mixin1 extends base { m1v1: string; m1v2: boolean; constructor(m1v1: string, m1v2: boolean, ...args: any[]) { super(...args); this.m1v1 = m1v1; this.m1v2 = m1v2; } } const mixin2 = <T extends Constructor>(base: T) => class Mixin2 extends base { m2v1: boolean; m2v2: number; constructor(m2v1: boolean, m2v2: number, ...args: any[]) { super(...args); this.m2v1 = m2v1; this.m2v2 = m2v2; } } class Base { v1: number; v2: object; constructor(v1: number, v2: object) { this.v1 = v1; this.v2 = v2; } } class C1 extends mixin1(Base) { } class C2 extends mixin2(Base) { } class C3 extends mixin2(mixin1(Ba…