test: make test-debug-process locale-independent

The test `test/parallel/test-debug-process.js` fails on non-English
Windows systems due to a locale-dependent error message string.

The test asserts that a call to `process._debugProcess()` on a
terminated process throws an error with the message
`'The system cannot find the file specified.'`.
While this holds true on an English Windows system,
the test fails on systems with a different display language.

The underlying `WinapiErrnoException` function correctly retrieves the
localized error message from the OS. For example, on a Korean system,
the message is "지정된 파일을 찾을 수 없습니다.". This mismatch causes
an `AssertionError`.

This behavior can be verified directly in PowerShell:

# On Windows with English (US) display language
PS> (New-Object System.ComponentModel.Win32Exception 2).Message
The system cannot find the file specified.

# On Windows with Korean display language
PS> (New-Object System.ComponentModel.Win32Exception 2).Message
지정된 파일을 찾을 수 없습니다.

To make the test robust and environment-agnostic, this commit changes
the assertion to check the language-independent `error.errno` property,
which is consistently `2` for this type of error, instead of the
localized `error.message`.

Author: Amemome

test/parallel/test-debug-process.js

@@ -16,6 +16,6 @@ cp.on('exit', common.mustCall(function() {
   try {
     process._debugProcess(cp.pid);
   } catch (error) {
-    assert.strictEqual(error.message, 'The system cannot find the file specified.');
+    assert.strictEqual(error.errno, 2);
   }
 }));