Fix #5042: Allow non-constant args for directionless action params in tables

[devalgupta404]

Summary

Fixes #5042

Per P4 Spec Section 6.8, directionless action parameters should behave as in when values are provided by the P4 program, and need not be compile-time known values.

The Problem

The compiler incorrectly rejected valid P4 code:

action a(bit<8> data) { hdr.h.f = data; }                                                                                                                                      
table t {                                                                                                                                                                      
    actions = { a; }                                                                                                                                                           
    default_action = a(meta.x);  // ERROR: action argument must be a compile-time constant                                                                                     
}                                                                                                                                                                              

The Fix

Removed the incorrect compile-time constant check for directionless parameters in actionCall() when used in table default_action or entries.

File: frontends/p4/typeChecking/typeCheckExpr.cpp:1895-1898

Testing

Before fix:
$ ./build/p4test testdata/p4_16_samples/issue5042.p4
error: meta.x: action argument must be a compile-time constant

After fix:
$ ./build/p4test testdata/p4_16_samples/issue5042.p4
$ echo $?
0

Regression test:
$ ctest -R "p4_16_samples" -j4
96% tests passed, 1529 of 1598
All 1301 p4 label tests passed. The 69 failures are pre-existing ebpf/ubpf backend issues unrelated to this change.