Control flow graph for safe calls corrected #KT-10913 Fixed

Also #KT-10186 Fixed
Also #KT-5198 Fixed

compiler/testData/cfg/deadCode/throwInLambda.kt

@@ -0,0 +1,16 @@
+// See KT-10913 Bogus unreachable code warning
+
+fun fn() : String? = null
+
+inline fun <T, R> T.let(f: (T) -> R): R = f(this)
+
+fun foo(): String {
+    val x = fn()?.let { throw Exception() } ?: "unreachable?"
+    return x
+}
+
+fun bar(): String {
+    val x = fn() ?: return ""
+    val y = x?.let { throw Exception() } ?: "unreachable"
+    return y
+}