Add heap performance markers

Author: Andy Hanson

src/compiler/checker.ts

@@ -19220,6 +19220,8 @@ namespace ts {
 
         function initializeTypeChecker() {
             // Bind all source files and propagate errors
+            performance.mark("heapBeforeBind");
+
             for (const file of host.getSourceFiles()) {
                 bindSourceFile(file, compilerOptions);
             }
@@ -19269,6 +19271,8 @@ namespace ts {
             // Setup global builtins
             addToSymbolTable(globals, builtinGlobals, Diagnostics.Declaration_name_conflicts_with_built_in_global_identifier_0);
 
+            performance.mark("heapAfterBind");
+
             getSymbolLinks(undefinedSymbol).type = undefinedWideningType;
             getSymbolLinks(argumentsSymbol).type = getGlobalType("IArguments");
             getSymbolLinks(unknownSymbol).type = unknownType;