[browser] Bundler friendly output

[maraf]

• New boot config schema allowing us to attach more information to individual assets
  • Instead of using simple dictionary, we now have an array of objects
  • Integrity is exported only for files that use it
• Module initializers now supports moduleExports instead of link to file as well
• A new msbuild property WasmBundlerFriendlyBootConfig which enables to generate boot config, this is not working in browsers on it's own, but can be preprocessed by transpilers like babel. Using rollup or webpack it can be configured to (for example):
  • Resolve wasm & other files as files, copying them to the output directory, optionally fingerprinting them
  • Embed wasm & other files as base64 encoded blobs directly into the javascript
• New Wasm.Build.Tests configuration running selected tests with WasmBundlerFriendlyBootConfig=true & repacking the publish output with rollup
  • To simplify the setup, it runs the tests only on publish output. Mainly because during build user files (eg main.js) aren't copied to the build output and so they can't be easily bundled into single file
  • CI is using npm installed into helix machines/docker images
  • Correct npm path resolution will be fixed in a follow-up

Sample boot config

//! Licensed to the .NET Foundation under one or more agreements.
//! The .NET Foundation licenses this file to you under the MIT license.

import * as dotnet_runtime_js from "./dotnet.runtime.js";
import * as dotnet_native_js from "./dotnet.native.js";
import dotnet_native_wasm from "./dotnet.native.wasm";
import System_Runtime_InteropServices_JavaScript_wasm from "./System.Runtime.InteropServices.JavaScript.wasm";
import System_Private_CoreLib_wasm from "./System.Private.CoreLib.wasm";
import System_Runtime_wasm from "./System.Runtime.wasm";
import RollupDotNet_wasm from "./RollupDotNet.wasm";
import * as __RollupDotNet_1uxdo6nju6_lib_module_js from "./../RollupDotNet.1uxdo6nju6.lib.module.js";
import * as ___2F_RollupDotNet_1uxdo6nju6_lib_module_js from "./../RollupDotNet.1uxdo6nju6.lib.module.js";
import ___2F_appsettings_json from "./../appsettings.json";

var WasmEnableThreads = false;

...

dotnet.withConfig(/*json-start*/{
  "mainAssemblyName": "RollupDotNet",
  "resources": {
    "hash": "sha256-6j4TfY4hqK2qKV90WC2cRVlNXjAaZ24ep5vJAmqiYrI=",
    "jsModuleNative": [
      {
        "name": "dotnet.native.js",
        "moduleExports": dotnet_native_js
      }
    ],
    "jsModuleRuntime": [
      {
        "name": "dotnet.runtime.js",
        "moduleExports": dotnet_runtime_js
      }
    ],
    "wasmNative": [
      {
        "name": "dotnet.native.wasm",
        "integrity": "sha256-M7SZyK2m4UwAOa84vukO1znsJ+yxlAxtSnpZKV+Z3ZI=",
        "resolvedUrl": dotnet_native_wasm
      }
    ],
    "coreAssembly": [
      {
        "virtualPath": "System.Runtime.InteropServices.JavaScript.wasm",
        "name": "System.Runtime.InteropServices.JavaScript.wasm",
        "integrity": "sha256-IdWvP/V/e1XXYvXDeG5pT3BwSL/VV5FtIC1AvIVNqDw=",
        "resolvedUrl": System_Runtime_InteropServices_JavaScript_wasm
      },
      {
        "virtualPath": "System.Private.CoreLib.wasm",
        "name": "System.Private.CoreLib.wasm",
        "integrity": "sha256-d+RzHESxTy3EAXcG7WPAGC5QfKO/+BlJnFQgtSxk3kg=",
        "resolvedUrl": System_Private_CoreLib_wasm
      }
    ],
    "assembly": [
      {
        "virtualPath": "System.Runtime.wasm",
        "name": "System.Runtime.wasm",
        "integrity": "sha256-RXtMA0t8B/vmiES29vtYhE7cqBD+j8spovTroyOaU4M=",
        "resolvedUrl": System_Runtime_wasm
      },
      {
        "virtualPath": "RollupDotNet.wasm",
        "name": "RollupDotNet.wasm",
        "integrity": "sha256-ADHfSUAIpH+Xnkhn9aGEPq0sBL+ZM2kM/lGZW7rK0ic=",
        "resolvedUrl": RollupDotNet_wasm
      }
    ],
    "libraryInitializers": [
      {
        "name": "RollupDotNet.1uxdo6nju6.lib.module.js",
        "moduleExports": __RollupDotNet_1uxdo6nju6_lib_module_js
      }
    ],
    "modulesAfterConfigLoaded": [
      {
        "name": "../RollupDotNet.1uxdo6nju6.lib.module.js",
        "moduleExports": ___2F_RollupDotNet_1uxdo6nju6_lib_module_js
      }
    ]
  },
  "debugLevel": 0,
  "linkerEnabled": true,
  "appsettings": [
    ___2F_appsettings_json
  ],
  "globalizationMode": "invariant",
  "runtimeConfig": {
    "runtimeOptions": {
      "configProperties": {
        ...
      }
    }
  }
}/*json-end*/);

Contributes to #77191
Fixes #86162

[akoeplinger]

One comment that should be addressed but LGTM otherwise

[maraf]

/ba-g Failures are not related