Allow setting breakpoints on ternary branches

[jnm2]

The penalty for using ternaries instead of if statements is that breakpoints can't be set for each branch. When you're in the middle of debugging, it's too late to refactor. Sometimes you can set a breakpoint on the whole statement and duplicate the effective condition, but this expression may be nested inside another ternary or in a long initializer expression; even when you can duplicate the condition without side effects, it's frustrating to put together.

Similar to #30645, possibly covered by #22016.

[jnm2]

Besides common debugging scenarios, another reason I'm really hoping for sequence points to be emitted for expressions is that Live Unit Testing (last I tried it), ReSharper's test coverage, and NCrunch all use statement or line granularity. The lack of expression granularity obfuscates the true branch coverage situation.

[jnm2]

When switch expressions arrive, this will become even more important.

[jinujoseph]

looks same as #22016 , cc @tmat

[tmat]

Yes, this is covered by #22016. I don't think we need to track it in multiple issues.

[jnm2]

Now tracked by #43092