[tautschnig]

boolbv_shift.cpp treated constant shift distances outside
[0, INT_MAX] as distance 0, effectively turning shifts by 2^31 or
larger into no-ops for the SAT backend and smt2_solver (which uses
the same code). For shifts, clamp the distance to the operand width
(shifting by at least the width zeros out all bits). For rotations,
reduce the distance modulo the width.

The SMT2 converter (smt2_conv.cpp) has a separate truncation issue
for shift distances wider than the operand, #9374, which #9178
addresses.

Fixes #9351

Found by Jeroen Robben's specification-conformance pipeline (https://reports.robben.io/methodology/).

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[kroening]

This needs a bit of thinking -- we need to distinguish C semantics from the semantics of the logic expression.

Do we want to give meaning to shifts that exceed the width of the LHS operand?

[kroening]

At the very, very least, I would not use a C program with UB as the test.