Add missing removeHeader() function to image optimizer mock res

[styfle]

• Related to Caching-related edge case in one of dependencies #27724
• Related to After restarting project and open in browser console throws errors #19309
• Related to Nextjs deployed in EC2 crashes with a.removeHeader is not a function error #23140

[ijjk]

Stats from current PR

Default Build (Decrease detected ✓)

General Overall increase ⚠️

	vercel/next.js canary	vercel/next.js fix-missing-removeHeader-func	Change
buildDuration	12.9s	12.8s	-19ms
buildDurationCached	3s	3s	-9ms
nodeModulesSize	50.1 MB	50.1 MB	⚠️ +326 B

Page Load Tests Overall decrease ⚠️

	vercel/next.js canary	vercel/next.js fix-missing-removeHeader-func	Change
/ failed reqs	0	0	✓
/ total time (seconds)	2.242	2.235	-0.01
/ avg req/sec	1115	1118.73	+3.73
/error-in-render failed reqs	0	0	✓
/error-in-render total time (seconds)	1.213	1.22	⚠️ +0.01
/error-in-render avg req/sec	2061.26	2049.77	⚠️ -11.49

Client Bundles (main, webpack, commons)

	vercel/next.js canary	vercel/next.js fix-missing-removeHeader-func	Change
745.HASH.js gzip	179 B	179 B	✓
framework-HASH.js gzip	42.2 kB	42.2 kB	✓
main-HASH.js gzip	23.1 kB	23.1 kB	✓
webpack-HASH.js gzip	1.5 kB	1.5 kB	✓
Overall change	67 kB	67 kB	✓

Legacy Client Bundles (polyfills)

	vercel/next.js canary	vercel/next.js fix-missing-removeHeader-func	Change
polyfills-HASH.js gzip	31.1 kB	31.1 kB	✓
Overall change	31.1 kB	31.1 kB	✓

Client Pages

	vercel/next.js canary	vercel/next.js fix-missing-removeHeader-func	Change
_app-HASH.js gzip	980 B	980 B	✓
_error-HASH.js gzip	194 B	194 B	✓
amp-HASH.js gzip	312 B	312 B	✓
css-HASH.js gzip	329 B	329 B	✓
dynamic-HASH.js gzip	2.52 kB	2.52 kB	✓
head-HASH.js gzip	350 B	350 B	✓
hooks-HASH.js gzip	904 B	904 B	✓
image-HASH.js gzip	4.13 kB	4.13 kB	✓
index-HASH.js gzip	261 B	261 B	✓
link-HASH.js gzip	1.66 kB	1.66 kB	✓
routerDirect..HASH.js gzip	319 B	319 B	✓
script-HASH.js gzip	387 B	387 B	✓
withRouter-HASH.js gzip	320 B	320 B	✓
bb14e60e810b..30f.css gzip	125 B	125 B	✓
Overall change	12.8 kB	12.8 kB	✓

Client Build Manifests

	vercel/next.js canary	vercel/next.js fix-missing-removeHeader-func	Change
_buildManifest.js gzip	492 B	492 B	✓
Overall change	492 B	492 B	✓

Rendered Page Sizes

	vercel/next.js canary	vercel/next.js fix-missing-removeHeader-func	Change
index.html gzip	531 B	531 B	✓
link.html gzip	542 B	542 B	✓
withRouter.html gzip	523 B	523 B	✓
Overall change	1.6 kB	1.6 kB	✓

---

Webpack 4 Mode (Decrease detected ✓)

General Overall increase ⚠️

	vercel/next.js canary	vercel/next.js fix-missing-removeHeader-func	Change
buildDuration	10.2s	10.4s	⚠️ +137ms
buildDurationCached	4.1s	4s	-111ms
nodeModulesSize	50.1 MB	50.1 MB	⚠️ +326 B

Page Load Tests Overall decrease ⚠️

	vercel/next.js canary	vercel/next.js fix-missing-removeHeader-func	Change
/ failed reqs	0	0	✓
/ total time (seconds)	2.261	2.27	⚠️ +0.01
/ avg req/sec	1105.59	1101.54	⚠️ -4.05
/error-in-render failed reqs	0	0	✓
/error-in-render total time (seconds)	1.235	1.248	⚠️ +0.01
/error-in-render avg req/sec	2024.46	2003.15	⚠️ -21.31

Client Bundles (main, webpack, commons)

	vercel/next.js canary	vercel/next.js fix-missing-removeHeader-func	Change
17.HASH.js gzip	185 B	185 B	✓
677f882d2ed8..HASH.js gzip	14 kB	14 kB	✓
framework.HASH.js gzip	41.9 kB	41.9 kB	✓
main-HASH.js gzip	10.5 kB	10.5 kB	✓
webpack-HASH.js gzip	1.19 kB	1.19 kB	✓
Overall change	67.8 kB	67.8 kB	✓

Legacy Client Bundles (polyfills)

	vercel/next.js canary	vercel/next.js fix-missing-removeHeader-func	Change
polyfills-HASH.js gzip	31.3 kB	31.3 kB	✓
Overall change	31.3 kB	31.3 kB	✓

Client Pages

	vercel/next.js canary	vercel/next.js fix-missing-removeHeader-func	Change
_app-HASH.js gzip	965 B	965 B	✓
_error-HASH.js gzip	3.74 kB	3.74 kB	✓
amp-HASH.js gzip	552 B	552 B	✓
css-HASH.js gzip	333 B	333 B	✓
dynamic-HASH.js gzip	2.71 kB	2.71 kB	✓
head-HASH.js gzip	2.97 kB	2.97 kB	✓
hooks-HASH.js gzip	911 B	911 B	✓
index-HASH.js gzip	231 B	231 B	✓
link-HASH.js gzip	1.64 kB	1.64 kB	✓
routerDirect..HASH.js gzip	298 B	298 B	✓
script-HASH.js gzip	2.94 kB	2.94 kB	✓
withRouter-HASH.js gzip	294 B	294 B	✓
e025d2764813..52f.css gzip	125 B	125 B	✓
Overall change	17.7 kB	17.7 kB	✓

Client Build Manifests

	vercel/next.js canary	vercel/next.js fix-missing-removeHeader-func	Change
_buildManifest.js gzip	499 B	499 B	✓
Overall change	499 B	499 B	✓

Rendered Page Sizes

	vercel/next.js canary	vercel/next.js fix-missing-removeHeader-func	Change
index.html gzip	577 B	577 B	✓
link.html gzip	589 B	589 B	✓
withRouter.html gzip	570 B	570 B	✓
Overall change	1.74 kB	1.74 kB	✓

Commit: da9cc95