Stop double-stacktrace in ASSERT failures
Stop double-stacktrace in ASSERT failures

We were getting the stack trace printed twice in assertion
failures (e.g. see the Description of Trac #14552).

This fixes it, by deleting code.

(c.f. Trac #14635 which reports the same bug in documentation).

shlevy/ghc,shlevy/ghc,sdiehl/ghc,sdiehl/ghc,sdiehl/ghc,sdiehl/ghc,sdiehl/ghc,shlevy/ghc,shlevy/ghc,shlevy/ghc,shlevy/ghc,sdiehl/ghc,shlevy/ghc,sdiehl/ghc