added ConstraintSystemTest

compiler/testData/constraintSystem/declarations/declarations.kt

@@ -0,0 +1,10 @@
+fun foo<T, P, Q, R, S>() = 42
+
+trait A
+trait B : A
+trait C : B
+
+trait Consumer<in T>
+trait Producer<out T>
+
+trait My<T>

compiler/testData/constraintSystem/simpleSuccessful.bounds

@@ -0,0 +1,18 @@
+VARIABLES T
+
+SUBTYPE T Int
+SUPERTYPE T Int !
+
+type parameter bounds:
+T >: Int(SPECIAL), <: Int(SPECIAL)
+status:
+-hasConflictingConstraints: false
+-hasContradiction: false
+-hasErrorInConstrainingTypes: false
+-hasTypeConstructorMismatch: false
+-hasUnknownParameters: false
+-hasViolatedUpperBound: false
+-isSuccessful: true
+
+result:
+T=Int