chore: move cli/tests/ -> tests/ (#22369)

This looks like a massive PR, but it's only a move from cli/tests ->
tests, and updates of relative paths for files.

This is the first step towards aggregate all of the integration test
files under tests/, which will lead to a set of integration tests that
can run without the CLI binary being built.

While we could leave these tests under `cli`, it would require us to
keep a more complex directory structure for the various test runners. In
addition, we have a lot of complexity to ignore various test files in
the `cli` project itself (cargo publish exclusion rules, autotests =
false, etc).

And finally, the `tests/` folder will eventually house the `test_ffi`,
`test_napi` and other testing code, reducing the size of the root repo
directory.

For easier review, the extremely large and noisy "move" is in the first
commit (with no changes -- just a move), while the remainder of the
changes to actual files is in the second commit.

tests/testdata/coverage/complex_test.ts

@@ -0,0 +1,39 @@
+import { complex } from "./complex.ts";
+
+Deno.test("complex", function () {
+  complex("foo", "bar", "baz");
+});
+
+Deno.test("sub process with stdin", async () => {
+  // ensure launching deno run with stdin doesn't affect coverage
+  const code = "console.log('5')";
+  // deno-lint-ignore no-deprecated-deno-api
+  const p = await Deno.run({
+    cmd: [Deno.execPath(), "run", "-"],
+    stdin: "piped",
+    stdout: "piped",
+  });
+  const encoder = new TextEncoder();
+  await p.stdin.write(encoder.encode(code));
+  await p.stdin.close();
+  const output = new TextDecoder().decode(await p.output());
+  p.close();
+  if (output.trim() !== "5") {
+    throw new Error("Failed");
+  }
+});
+
+Deno.test("sub process with deno eval", async () => {
+  // ensure launching deno eval doesn't affect coverage
+  const code = "console.log('5')";
+  // deno-lint-ignore no-deprecated-deno-api
+  const p = await Deno.run({
+    cmd: [Deno.execPath(), "eval", code],
+    stdout: "piped",
+  });
+  const output = new TextDecoder().decode(await p.output());
+  p.close();
+  if (output.trim() !== "5") {
+    throw new Error("Failed");
+  }
+});