Currently we convert objects to strings using `'' + value` which is quickest,
but it stringifies the value using its `valueOf`, rather than `toString`. These
changes switch to using `String(value)` which has identical performance
and calls the `toString` method as expected. Note that another option
was calling `toString` directly, but benchmarking showed it to be slower.
I've included the benchmark I used to verify the performance so we have it
for future reference and we can reuse it when making changes to `renderStringify`
in the future.
Also for reference, here are the results of the benchmark:
```
Benchmark: renderStringify
concat: 2.006 ns(0%)
concat with toString: 2.201 ns(-10%)
toString: 237.494 ns(-11741%)
toString with toString: 121.072 ns(-5937%)
constructor: 2.201 ns(-10%)
constructor with toString: 2.201 ns(-10%)
toString mono: 14.536 ns(-625%)
toString with toString mono: 9.757 ns(-386%)
```
Fixes#38839.
PR Close#39843
11cd37fae3