specs: skip or conditionally spy on console.error when it's not spyable

GJS defines console.error as a non-writable, non-configurable property.
SpyRegistry checks the property descriptor and throws:
  Error: <spyOn> : error is not declared writable or has no setter

Add guards to skip or conditionally execute tests that spy on
console.error when the property is not spyable. This affects:
- DeprecatorSpec: skip all #deprecate tests via beforeEach
- DeprecationSpec: skip all integration tests via beforeEach
- EnvSpec: skip the deprecation stack test
- baseSpec: conditionally spy on console.error in the setTimeout test

Author: amezin

spec/core/DeprecatorSpec.js

@@ -2,6 +2,12 @@
 describe('Deprecator', function() {
   describe('#deprecate', function() {
     beforeEach(function() {
+      const descriptor = Object.getOwnPropertyDescriptor(console, 'error');
+      if (descriptor && !(descriptor.writable || descriptor.set)) {
+        pending('console.error is not spyable in this environment');
+        return;
+      }
+
       spyOn(console, 'error');
     });
 

spec/core/baseSpec.js

@@ -156,7 +156,18 @@ describe('base helpers', function() {
       if (typeof process !== 'undefined' && process.emitWarning) {
         spyOn(process, 'emitWarning'); // Node 22
       }
-      spyOn(console, 'error'); // Node <22
+
+      const consoleErrorDescriptor = Object.getOwnPropertyDescriptor(
+        console,
+        'error'
+      );
+      if (
+        !consoleErrorDescriptor ||
+        consoleErrorDescriptor.writable ||
+        consoleErrorDescriptor.set
+      ) {
+        spyOn(console, 'error'); // Node <22
+      }
 
       let id = setTimeout(f1, max);
       setTimeout(function() {

spec/core/integration/DeprecationSpec.js

@@ -2,7 +2,17 @@
 describe('Deprecation (integration)', function() {
   let env;
 
+  function consoleErrorIsSpyable() {
+    const descriptor = Object.getOwnPropertyDescriptor(console, 'error');
+    return !descriptor || descriptor.writable || descriptor.set;
+  }
+
   beforeEach(function() {
+    if (!consoleErrorIsSpyable()) {
+      pending('console.error is not spyable in this environment');
+      return;
+    }
+
     env = new privateUnderTest.Env();
   });
 

spec/core/integration/EnvSpec.js

@@ -2945,6 +2945,12 @@ describe('Env integration', function() {
   });
 
   it('should report deprecation stack with an error object', async function() {
+    const descriptor = Object.getOwnPropertyDescriptor(console, 'error');
+    if (descriptor && !(descriptor.writable || descriptor.set)) {
+      pending('console.error is not spyable in this environment');
+      return;
+    }
+
     const exceptionFormatter = new privateUnderTest.ExceptionFormatter();
     const reporter = jasmine.createSpyObj('reporter', [
       'jasmineDone',