Enable suspend conversions by default in 1.6

^KT-48618 Fixed

compiler/testData/codegen/box/suspendConversion/basicSuspendConversionDefault.kt

@@ -0,0 +1,27 @@
+// IGNORE_BACKEND: JVM
+// IGNORE_BACKEND: WASM
+
+// !DIAGNOSTICS: -UNUSED_PARAMETER
+
+fun foo1(f: suspend () -> String) {}
+fun foo2(f: suspend (Int) -> String) {}
+fun foo3(f: suspend () -> Unit) {}
+
+fun test(
+    f0: suspend () -> String,
+    f1: () -> String,
+    f2: (Int) -> String,
+    f3: () -> Unit,
+) {
+    foo1 { "str" }
+    foo1(f0)
+
+    foo1(f1)
+    foo2(f2)
+    foo3(f3)
+}
+
+fun box(): String {
+    test({ "" }, { "" }, { it.toString() }, {})
+    return "OK"
+}