Merge #20379: tests: Remove no longer needed UBSan suppression (float divide-by-zero in validation.cpp)

0ccb3ad tests: Remove no longer needed UBSan suppression (float-divide-by-zero in validation.cpp) (practicalswift)

Pull request description:

  Remove no longer needed UBSan suppression.

  The float divide-by-zero in `validation.cpp` was fixed by instagibbs in ec30a79 (#15283).

ACKs for top commit:
  MarcoFalke:
    ACK 0ccb3ad

Tree-SHA512: 89a4f4b7371fa5725d9f801cee7ebbd17523f66017c9acfa813657dcb8d837f42209eff44ce9e5d48296a630bab9599d75f10024a0c7da7defb228f4eae3392a

Author: MarcoFalke

test/sanitizer_suppressions/ubsan

@@ -1,7 +1,3 @@
-# -fsanitize=undefined suppressions
-# =================================
-float-divide-by-zero:validation.cpp
-
 # -fsanitize=integer suppressions
 # ===============================
 # Unsigned integer overflow occurs when the result of an unsigned integer