Add comprehensive tests for cuddAddIte.c targeting 90% coverage

[Copilot]

Adds test coverage for src/cuddAddIte.c which implements ADD ITE operations and related functions. Initial coverage was 8.6%.

Changes

• Cudd_addIte tests: Constant selectors (f=0, f=1), g==h case, ITE(F,1,0)=F shortcut, addVarToConst conversions (f==g, f==h), F=(x,1,0) and F=(x,0,1) shortcuts
• Cudd_addIteConstant tests: Trivial cases, constant g/h returning DD_NON_CONSTANT, recursive paths with cache hits
• Cudd_addEvalConst tests: Terminal cases (f=1, f=0, g constant), recursive cases with Fv==zero and Fnv!=zero branches
• Cudd_addCmpl tests: Complement of 0/1/non-zero constants, complex ADDs, cache hit verification
• Cudd_addLeq tests: f==g, constant comparisons, PLUS/MINUS_INFINITY edge cases, recursive cofactor traversal
• cuddAddIteRecur/cuddAddCmplRecur tests: t==e optimization, topf>v cofactor case

SECTION("ITE(F,1,0) returns F") {
    DdNode *var0 = Cudd_addIthVar(manager, 0);
    Cudd_Ref(var0);
    DdNode *result = Cudd_addIte(manager, var0, one, zero);
    REQUIRE(result == var0);
    Cudd_RecursiveDeref(manager, var0);
}

Original prompt

Complete test cases for src/cuddAddIte.c and target 90% coverage for the source file.

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