This removes an inaccurate check that doesn't set a revalidate value if
revalidate is `undefined` which can be the case for SSR app route pages.
Also adds a regression test to ensure this doesn't break again.

Fixes: #70213
# Conflicts:
#	packages/next/src/server/base-server.ts

### Why?

Since `URL.canParse` is incompatible with older browsers like Safari 16,
we added `canParseUrl` util at
#70215.
x-ref: https://caniuse.com/?search=URL.canParse

To improve maintenance, we decided to add polyfill for `URL.canParse`.
x-ref: [slack
thread](https://vercel.slack.com/archives/C07BVA6HM17/p1726664071636899?thread_ts=1726620161.450109&cid=C07BVA6HM17)

Closes NDX-302

---------

Co-authored-by: Jiachi Liu <inbox@huozhi.im>
# Conflicts:
#	packages/next/src/lib/url.ts
#	packages/next/src/server/lib/router-server.ts
#	pnpm-lock.yaml

# Conflicts:
#	pnpm-lock.yaml

### What?

Fixes the error `Cannot read property 'startTime' of null` on Chrome 74
for Android 9 by ensuring the `beforeHydrationMeasure` and
`hydrationMeasure` are not falsy values before accessing their
properties.

<img width="1164" alt="Screenshot 2024-07-02 at 11 14 53 PM"
src="https://github.com/vercel/next.js/assets/52588326/34df95b6-a4fe-4886-96b8-a3c873a2ae6a">

### Why?

The application crashes on Chrome 74 for Android 9 due to `null` or
other falsy values being returned in certain situations. This fix
ensures that the `startTime` property is only accessed if it is not a
falsy value, thereby preventing the crash.

### How?

Added a falsy check before accessing the `startTime` property in the
performance measurement logic. Specifically, modified the code at [this
location](https://github.com/vercel/next.js/blob/b9bd23baec14508400c502b3651f4cf2497e883b/packages/next/src/client/index.tsx#L498)

Co-authored-by: JJ Kasper <jj@jjsweb.site>