feat: warn when using --unstable, prefer granular flags (#21452)

This commit deprecates "--unstable" flag. 

When "--unstable" flag is encountered a warning like this is printed:
```
The `--unstable` flag is deprecated, use granular `--unstable-*` flags instead.
Learn more at: https://docs.deno.com/runtime/manual/tools/unstable_flags
```
When "--unstable" flag is used and an unstable API is called an
additional warning like this is printed for each API call:
```
The `Deno.dlopen` API was used with `--unstable` flag. The `--unstable` flag is deprecated, use granular `--unstable-ffi` instead. 
Learn more at: https://docs.deno.com/runtime/manual/tools/unstable_flags
```
When no "--unstable-*" flag is provided and an unstable API is called
following
warning is issued before exiting:
```
Unstable API 'Deno.dlopen'. The `--unstable-ffi` flag must be provided.
```

---------

Signed-off-by: Divy Srivastava <dj.srivastava23@gmail.com>
Signed-off-by: Bartek Iwańczuk <biwanczuk@gmail.com>
Co-authored-by: Divy Srivastava <dj.srivastava23@gmail.com>
Co-authored-by: Asher Gomez <ashersaupingomez@gmail.com>

1 files changed, 1 insertions, 1 deletions

diff --git a/cli/tests/testdata/npm/registry/@denotest/child-process-fork/1.0.0/index.js b/cli/tests/testdata/npm/registry/@denotest/child-process-fork/1.0.0/index.js
index 9f84afe35..0482be404 100644
--- a/cli/tests/testdata/npm/registry/@denotest/child-process-fork/1.0.0/index.js
+++ b/cli/tests/testdata/npm/registry/@denotest/child-process-fork/1.0.0/index.js
@@ -2,7 +2,7 @@ const path = require("path");
 
 function childProcessFork(path) {
   const command = new Deno.Command(Deno.execPath(), {
-    args: ["run", "--unstable", "-A", path],
+    args: ["run", "-A", path],
     env: {
       "DENO_DONT_USE_INTERNAL_NODE_COMPAT_STATE": Deno[Deno.internal].core.ops.op_npm_process_state(),
     }