Refactor `stackTrace` in the `vm` implementation

[haxscramper]

VM rawExecute uses an implicitly injected return statement that is added by template stackTrace(). This makes code much harder to read, since you can't properly see where the loop is terminated.

template stackTrace(
    c: PCtx,
    tos: PStackFrame,
    pc: int,
    sem: ReportTypes,
  ) =
  stackTraceImpl(c, tos, pc, c.debug[pc], instLoc())
  localReport(c.config, c.debug[pc], sem)
- return

Remove implicitly injected return and add it in a way that is visible to the reader.

    of opcLdArr:
      # a = b[c]
      decodeBC(rkNode)
      if regs[rc].intVal > high(int):
        stackTrace(c, tos, pc, reportVmIdx(regs[rc].intVal, high(int)))
+       return

Hint: in order to track all the usages of the stackTrace template, you can add {.hint: "used here".} or {.warning: "used here".}