Add type inference logic for map literals

pkg/front_end/testcases/inference/inferred_nonstatic_field_depends_on_static_field_complex.dart.strong.expect

Index: pkg/front_end/testcases/inference/inferred_nonstatic_field_depends_on_static_field_complex.dart.strong.expect
diff --git a/pkg/front_end/testcases/inference/inferred_nonstatic_field_depends_on_static_field_complex.dart.strong.expect b/pkg/front_end/testcases/inference/inferred_nonstatic_field_depends_on_static_field_complex.dart.strong.expect
new file mode 100644
index 0000000000000000000000000000000000000000..65dcc6915910b588019c97685ddc217fbcf2b224
--- /dev/null
+++ b/pkg/front_end/testcases/inference/inferred_nonstatic_field_depends_on_static_field_complex.dart.strong.expect
@@ -0,0 +1,12 @@
+library test;
+import self as self;
+import "dart:core" as core;
+
+class C extends core::Object {
+  static field core::String x = "x";
+  field core::Map<core::String, core::Map<core::String, core::String>> y = <core::String, core::Map<core::String, core::String>>{"a": <core::String, core::String>{"b": "c"}, "d": <core::String, core::String>{"e": self::C::x}};
+  constructor •() → void
+    : super core::Object::•()
+    ;
+}
+static method main() → dynamic {}