Revise mismatch tests so they don't rely on undefined behavior

Revise mismatch tests so they don't rely on undefined behavior

The mismatch32 and mismatch64 tests ensure that the jit will avoid
inlining in cases where there are bad type mismatches at call sites.

This change modifies the tests so that by default the call with the
bad type mismatch is not hit at runtime, since execution of this code
exposes undefined behavior that can be arch or jit specific (eg failing
on x86 and passing on other architectures).

The problematic call can still be hit at runtime by passing at least one
command line argument.

Remove the associated test exclusions for x86.

Fixes #8152.