[Clang] call HandleImmediateInvocation before checking for immediate escacalating expressions (#124414)
HandleImmediateInvocation can call MarkExpressionAsImmediateEscalating
and should always be called before
CheckImmediateEscalatingFunctionDefinition.
However, we were not doing that in `ActFunctionBody`.
We simply move CheckImmediateEscalatingFunctionDefinition to
PopExpressionEvaluationContext.
Fixes #119046