Reorganize codegen tests for old language versions

Put all files under a single "oldLanguageVersions" directory under test
data of each test

compiler/testData/codegen/bytecodeText/oldLanguageVersions/ieee754/nullableDoubleEquals10.kt

@@ -0,0 +1,29 @@
+// !API_VERSION: 1.0
+
+fun myEquals(a: Double?, b: Double?) = a == b
+
+fun myEquals1(a: Double?, b: Double) = a == b
+
+fun myEquals2(a: Double, b: Double?) = a == b
+
+fun myEquals0(a: Double, b: Double) = a == b
+
+
+fun box(): String {
+    if (!myEquals(null, null)) return "fail 1"
+    if (myEquals(null, 0.0)) return "fail 2"
+    if (myEquals(0.0, null)) return "fail 3"
+    if (!myEquals(0.0, 0.0)) return "fail 4"
+
+    if (myEquals1(null, 0.0)) return "fail 5"
+    if (!myEquals1(0.0, 0.0)) return "fail 6"
+
+    if (myEquals2(0.0, null)) return "fail 7"
+    if (!myEquals2(0.0, 0.0)) return "fail 8"
+
+    if (!myEquals0(0.0, 0.0)) return "fail 9"
+
+    return "OK"
+}
+
+// 0 areEqual