[FIR] Freeze the current behavior of ImplicitIntegerCoercion+overloads

Adding the tests "just in case", ensuring the
K2 behaves similar to K1.

compiler/testData/diagnostics/tests/unsignedTypes/conversions/implicitIntegerCoercionOverloading.fir.kt

@@ -0,0 +1,25 @@
+// ISSUE: KT-57655
+// !LANGUAGE: +ImplicitSignedToUnsignedIntegerConversion
+// ALLOW_KOTLIN_PACKAGE
+
+// FILE: annotation.kt
+
+package kotlin.internal
+
+annotation class ImplicitIntegerCoercion
+
+// FILE: test.kt
+
+import kotlin.internal.ImplicitIntegerCoercion
+
+fun test(@ImplicitIntegerCoercion x: UInt) = x
+fun test(@ImplicitIntegerCoercion x: ULong) = x
+fun testLong(@ImplicitIntegerCoercion x: ULong) = x
+
+fun box(): String = when {
+    test(5) != 5.toUInt() -> "Fail: test(5)"
+    <!NONE_APPLICABLE!>test<!>(5L) != 5L.toULong() -> "Fail: test(5L)"
+    testLong(5) != 5L.toULong() -> "Fail: test(5L)"
+    testLong(<!ARGUMENT_TYPE_MISMATCH!>5L<!>) != 5L.toULong() -> "Fail: test(5L)"
+    else -> "OK"
+}

compiler/testData/diagnostics/tests/unsignedTypes/conversions/implicitIntegerCoercionOverloading.kt

@@ -0,0 +1,25 @@
+// ISSUE: KT-57655
+// !LANGUAGE: +ImplicitSignedToUnsignedIntegerConversion
+// ALLOW_KOTLIN_PACKAGE
+
+// FILE: annotation.kt
+
+package kotlin.internal
+
+annotation class ImplicitIntegerCoercion
+
+// FILE: test.kt
+
+import kotlin.internal.ImplicitIntegerCoercion
+
+fun test(@ImplicitIntegerCoercion x: UInt) = x
+fun test(@ImplicitIntegerCoercion x: ULong) = x
+fun testLong(@ImplicitIntegerCoercion x: ULong) = x
+
+fun box(): String = when {
+    test(5) != 5.toUInt() -> "Fail: test(5)"
+    <!EQUALITY_NOT_APPLICABLE!>test(<!CONSTANT_EXPECTED_TYPE_MISMATCH!>5L<!>) != 5L.toULong()<!> -> "Fail: test(5L)"
+    testLong(5) != 5L.toULong() -> "Fail: test(5L)"
+    testLong(<!CONSTANT_EXPECTED_TYPE_MISMATCH!>5L<!>) != 5L.toULong() -> "Fail: test(5L)"
+    else -> "OK"
+}