test: Modified to a more strict type

[koji-1009]

ref #178

Support for more strict type requirements in wasm build.

[jonasfj]

Is this a known issue? If not it might be interesting to make a minimum reproducible example and file an issue against the SDK.

It seems like it would be nice if there was a page somewhere with known compatibility issues between Dart when compiled the JS and wasm, respectively.

[koji-1009]

Comparing JSArray<JSString> with <String>[] shows that it does not implements Iterable. Running the test on the feat/replace_html branch will result in the following test fail.

To run this test again: /Users/koji/flutter/bin/cache/dart-sdk/bin/dart test test/crypto_subtle_test.dart -p chrome --plain-name 'crypto getRandomValues: not supported type'
00:09 +1415 -14: test/crypto_subtle_test.dart: crypto.subtle generateCryptoKey: success [E]
  Expected: <Instance of 'JSValue'> with `type`: 'secret' and `extractable`: <false> and `usages`: contains all of ['encrypt', 'decrypt']
    Actual: JSValue:<[object CryptoKey]>
     Which: has `usages` with value JSValue:<encrypt,decrypt> which not an <Instance of 'Iterable'>

I think it is because JSString and String are converted by js_interop, but JSArray and List are not. it is true that dart2wasm is more type strict than dart2js, but it is certainly not convenient.