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Hide implementation details of `throw` and `throwSTM`

Hannes Siebenhandl requested to merge wip/fendor/freeze-throw into master

Closes #26808 (closed)

throw exposed implementation details as it doesn't freeze the CallStack:

HasCallStack backtrace:
  collectExceptionAnnotation, called at libraries/ghc-internal/src/GHC/Internal/Exception.hs:170:37 in ghc-internal:GHC.Internal.Exception
  toExceptionWithBacktrace, called at libraries/ghc-internal/src/GHC/Internal/Exception.hs:90:42 in ghc-internal:GHC.Internal.Exception
  throw, called at T26806b.hs:17:9 in main:Main

The functions collectExceptionAnnotation and toExceptionWithBacktrace are implementation details of throw that are noise to the end user.

Thus, we freeze the CallStack, no longer exposing these details.

Then the backtrace looks like:

HasCallStack backtrace:
  throw, called at T26806b.hs:17:9 in main:Main

We do the same thing for throwSTM.

Further, we add regression tests to make sure that the stack traces do not accidentally

Edited by Hannes Siebenhandl

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