fix: correct acorn-walk ancestor visitor signature and ts-expect-error in tests

acorn-walk's ancestor() visitor signature is (node, state, ancestors) —
the previous code used (node, ancestors) so ancestors was actually
receiving the state arg (undefined at runtime), causing a crash when
accessing ancestors.length and TypeScript errors about unknown types.

The direct `import.meta.env = ...` assignments in tests are read-only
per TypeScript's ImportMeta, but vitest's MetaEnvReplacerPlugin rewrites
them at runtime. Added // @ts-expect-error to suppress the compile-time
error in all three test files.

Author: DaveT1991

packages/vitest/src/node/plugins/metaEnvReplacer.ts

@@ -36,7 +36,7 @@ export function MetaEnvReplacerPlugin(): Plugin {
       const assignmentRanges: Array<{ start: number; end: number }> = []
 
       walkAst(ast as any, {
-        MemberExpression(node, ancestors) {
+        MemberExpression(node, _state, ancestors) {
           if (!isImportMetaEnv(node)) {
             return
           }

test/browser/test/env.test.ts

@@ -15,6 +15,7 @@ test('can reassign import.meta.env directly', () => {
 
   delete import.meta.env[key]
 
+  // @ts-expect-error -- vitest rewrites this assignment at runtime via MetaEnvReplacerPlugin
   import.meta.env = import.meta.env || {}
   import.meta.env[key] = 'true'
 

test/core/test/env-jsdom.test.ts

@@ -29,6 +29,7 @@ test('can reassign import.meta.env directly', () => {
 
   delete process.env[key]
 
+  // @ts-expect-error -- vitest rewrites this assignment at runtime via MetaEnvReplacerPlugin
   import.meta.env = import.meta.env || {}
   import.meta.env[key] = 'true'
 

test/core/test/env.test.ts

@@ -27,6 +27,7 @@ test('can reassign import.meta.env directly', () => {
 
   delete process.env[key]
 
+  // @ts-expect-error -- vitest rewrites this assignment at runtime via MetaEnvReplacerPlugin
   import.meta.env = import.meta.env || {}
   import.meta.env[key] = 'true'