Lift try..catch out of an expression and replace with a temporary variable

[ChrisJollyAU]

When EnableDetailedErrors is turned on it wraps the expression to read the field value in a try...catch statement

In certain situations this is not valid C#

• When the expression is an argument to a method call
• Assignment of the right hand expression to a variable or instance member
• When the expression is part of a list
  • List of expressions for array initialize
  • List of expressions for the constructor with a NewExpression

Also fixed some of the catch handling

• ThrowExtractJsonPropertyException needs to be public for it to be called (like ThrowReadValueException already is)
• One place needed to refer to property.Name rather than just property
• There is a case where property is null so handle that for the call to ThrowReadValueException as well

Fixes #34393

[roji]

@ChrisJollyAU thanks for submitting this - this is generally a non-trivial part of EF.

Just to set expectations, it will probably be quite a while before we're able to review this - we're currently heads-down in 9.0 stabilization, docs and various other activities... But we definitely plan to do substantial work on (and hopefully finalize) the NativeAOT support in 10, and this would be part of that.