cli: add --expose-gc flag available to NODE_OPTIONS

This commits allows users to send `--expose-gc` via `NODE_OPTIONS`
environment variable.

Using `node --expose-gc` is possible but via `NODE_OPTIONS` won't
work.

```sh
NODE_OPTIONS='--expose-gc' node
node: --expose-gc is not allowed in NODE_OPTIONS
```

Signed-off-by: Juan José Arboleda <soyjuanarbol@gmail.com>

Author: juanarbol

doc/api/cli.md

@@ -3118,6 +3118,8 @@ documented here:
 
 ### `--max-old-space-size=SIZE` (in megabytes)
 
+### `--expose-gc`
+
 Sets the max memory size of V8's old memory section. As memory
 consumption approaches the limit, V8 will spend more time on
 garbage collection in an effort to free unused memory.

src/node_options.cc

@@ -473,6 +473,7 @@ EnvironmentOptionsParser::EnvironmentOptionsParser() {
   AddOption("--experimental-report", "", NoOp{}, kAllowedInEnvvar);
   AddOption(
       "--experimental-wasi-unstable-preview1", "", NoOp{}, kAllowedInEnvvar);
+  AddOption("--expose-gc", "expose gc extension", V8Option{}, kAllowedInEnvvar);
   AddOption("--expose-internals", "", &EnvironmentOptions::expose_internals);
   AddOption("--frozen-intrinsics",
             "experimental frozen intrinsics support",