browser: reduce races in evaluate*

[mstoykov]

What?

Reduce the number of sobek.Runtime used in page.evaluate that are off the event loop

Why?

This is racy and very likely the underlying cause of #4085 - although without a runnable example, it is impossible to check.

Unfortunately some of the usage for evalueateHandle will require even more changes. In order to provide some fixes I opted to not try to fix everything in one go.

Checklist

• I have performed a self-review of my code.
• I have added tests for my changes.
• I have run linter locally (make lint) and all checks pass.
• I have run tests locally (make tests) and all tests pass.
• I have commented on my code, particularly in hard-to-understand areas.

Related PR(s)/Issue(s)

Possibly fixing #4085