Move AST transforms out of the Frontend

Move the playground and debugger transforms out
of the Frontend and into `performTypeChecking`, as
we'd want them to be applied if
`performTypeChecking` was called lazily.

include/swift/Basic/LangOptions.h

@@ -139,10 +139,27 @@ namespace swift {
     /// Allow throwing call expressions without annotation with 'try'.
     bool EnableThrowWithoutTry = false;
 
+    /// If set, inserts instrumentation useful for testing the debugger.
+    bool DebuggerTestingTransform = false;
+
+    /// Indicates whether the AST should be instrumented to simulate a
+    /// debugger's program counter. Similar to the PlaygroundTransform, this
+    /// will instrument the AST with function calls that get called when you
+    /// would see a program counter move in a debugger. To adopt this implement
+    /// the __builtin_pc_before and __builtin_pc_after functions.
+    bool PCMacro = false;
+
     /// Enable features useful for running playgrounds.
     // FIXME: This should probably be limited to the particular SourceFile.
     bool Playground = false;
 
+    /// Indicates whether the playground transformation should be applied.
+    bool PlaygroundTransform = false;
+
+    /// Indicates whether the playground transformation should omit
+    /// instrumentation that has a high runtime performance impact.
+    bool PlaygroundHighPerformance = false;
+
     /// Keep comments during lexing and attach them to declarations.
     bool AttachCommentsToDecls = false;