Debugger pauses on wrong line with debugger() in catch block

[DanTup]

Raised by @4amVim at Dart-Code/Dart-Code#3337. I could repro using the supplied Flutter sample in Android Studio too, though was also able to reduce it to a standard CLI script using latest nightly build:

import 'dart:developer';

void main() {
  try {
    throw 'a';
  } catch (e) {
    debugger();
  }
  print('debugger pauses here');
}

The pause event has tokenPos: 101, and the tokenPosTable looks like this:

[
	[3,26,1,31,6,35,10,38,13],
	[4,46,7],
	[5,52,5],
	[6,65,3,67,5,74,12,77,15],
	[7,83,5],
	[8,97,3],
	[9,101,3], // Token 101 is on line 9
	[10,132,1]
]

This prevents examining the e variable since it appears to have gone out of scope.

[mkustermann]

/cc @aam

[aam]

This is due to the fact that debugger() gets dart program to stop after the call is completed (

sdk/sdk/lib/developer/developer.dart

Line 20 in 55e7119

/// was hit. The breakpoint will be placed right after the call to `debugger`.

), but there is no next available stopping point from vm perspective until program execution leaves the catch block and gets to print statement.
Potentially we could introduce such a stopping point - see https://dart-review.googlesource.com/c/sdk/+/310779

cc @a-siva