Ensure type of a stack value is coerced to the expected return type after the binary operation instruction with the different return type.

compiler/testData/codegen/box/binaryOp/overflowChar.kt

@@ -0,0 +1,10 @@
+fun box(): String {
+    val c1: Char = 0.toChar()
+    val c2 = c1 - 1
+    if (c2 < c1) return "fail: 0.toChar() - 1 should overflow to positive."
+
+    val c3 = c2 + 1
+    if (c3 > c2) return "fail: FFFF.toChar() + 1 should overflow to zero."
+
+    return "OK"
+}