FIR: Fix invalid INITIALIZER_TYPE_MISMATCH for suspend lambda

compiler/testData/diagnostics/tests/coroutines/suspendLambdaFromExpectedType.kt

@@ -0,0 +1,10 @@
+// FIR_IDENTICAL
+// SKIP_TXT
+
+fun <T> runBlocking(block: suspend () -> T): T = TODO()
+
+fun foo() = runBlocking<Unit> {
+    val foo: suspend (String) -> Int = {
+        it.length
+    }
+}