Attempt to finish off araq cpp exceptions (#13695)

* config update
* disable a questionable test
* remove c++ exception handling IDs, new impl doesn't require it anymore
* C++ based exceptions finally work
* fixes bootstrapping problem in C++ mode
* teach GCC it's 2020 now
* more bugfixes for C++ based exception handling
* apply cooldome's patch
* another attempt to enable C++11
* bug fix

Co-authored-by: Araq <rumpf_a@web.de>
Co-authored-by: cooldome <ariabushenko@bk.ru>

tests/cpp/tcppraise.nim

@@ -68,4 +68,4 @@ except:
   echo getCurrentExceptionMsg()
   discard
 
-doAssert: getCurrentException() == nil
+doAssert: getCurrentException() == nil

tests/cpp/tterminate_handler.nim

@@ -2,8 +2,9 @@ discard """
   targets: "cpp"
   outputsub: "Error: unhandled unknown cpp exception"
   exitcode: 1
+  disabled: true
 """
 type Crap {.importcpp: "int".} = object
 
 var c: Crap
-raise c
+raise c