Improve error reporting for FRAME Macros

[gupnik]

Generally within FRAME, the macro expansion exits as soon as some condition fails without generating rest of the code. This produces a cascade of errors resulting in poor dev experience.

Though it is not possible to fix it everywhere, a number of scenarios could be improved by aggregating all errors during the parsing phase and making the expansion phase infallible - but adding the aggregated errors along with the expansion.

#3478 serves as a good example.

CC: @bkchr @kianenigma

[kianenigma]

related: #334

[kianenigma]

but isn't this a duplicate of #213?

[gupnik]

but isn't this a duplicate of #213?

Wasn't aware of it. Will close this one.