test: mark flaky proxy tests (#13050)

tests/browsercontext-proxy.spec.ts

@@ -109,7 +109,7 @@ it.describe('should proxy local network requests', () => {
         }
       ]) {
         it(`${params.description}`, async ({ platform, browserName, contextFactory, server, proxyServer }) => {
-          it.fail(browserName === 'webkit' && platform === 'darwin' && additionalBypass && ['localhost', '127.0.0.1'].includes(params.target), 'WK fails to proxy 127.0.0.1 and localhost if additional bypasses are present');
+          it.fixme(browserName === 'webkit' && platform === 'darwin' && ['localhost', '127.0.0.1'].includes(params.target), 'Flaky on macOS; needs investigation.');
 
           const path = `/target-${additionalBypass}-${params.target}.html`;
           server.setRoute(path, async (req, res) => {

tests/proxy.spec.ts

@@ -91,7 +91,7 @@ it.describe('should proxy local network requests', () => {
         }
       ]) {
         it(`${params.description}`, async ({ platform, browserName, browserType, server, proxyServer }) => {
-          it.fail(browserName === 'webkit' && platform === 'darwin' && additionalBypass && ['localhost', '127.0.0.1'].includes(params.target), 'WK fails to proxy 127.0.0.1 and localhost if additional bypasses are present');
+          it.fixme(browserName === 'webkit' && platform === 'darwin' && ['localhost', '127.0.0.1'].includes(params.target), 'Flaky on macOS; needs investigation.');
 
           const path = `/target-${additionalBypass}-${params.target}.html`;
           server.setRoute(path, async (req, res) => {