Move all the builtin$ interceptors to a new interceptors library and shorten the names of them.

lib/compiler/implementation/ssa/builder.dart

Index: lib/compiler/implementation/ssa/builder.dart
diff --git a/lib/compiler/implementation/ssa/builder.dart b/lib/compiler/implementation/ssa/builder.dart
index 594d87f01d11369b51865f0150cbb9742f062518..f811be2c01165230a5c13548a3807ba9a1295998 100644
--- a/lib/compiler/implementation/ssa/builder.dart
+++ b/lib/compiler/implementation/ssa/builder.dart
@@ -44,18 +44,27 @@ class Interceptors {
   }
 
   Element getStaticInterceptor(SourceString name, int parameters) {
-    String mangledName = "builtin\$${name.slowToString()}\$${parameters}";
-    return compiler.findHelper(new SourceString(mangledName));
+    String mangledName = name.slowToString();
+    Element element = compiler.findInterceptor(new SourceString(mangledName));
+    if (element !== null && element.isFunction()) {
+      // Only pick the function element with the short name if the
+      // number of parameters it expects matches the number we're
+      // passing modulo the receiver.
+      FunctionElement function = element;
+      if (function.parameterCount(compiler) == parameters + 1) return element;
+    }
+    String longMangledName = "$mangledName\$$parameters";
+    return compiler.findInterceptor(new SourceString(longMangledName));
   }
 
   Element getStaticGetInterceptor(SourceString name) {
-    String mangledName = "builtin\$get\$${name.slowToString()}";
-    return compiler.findHelper(new SourceString(mangledName));
+    String mangledName = "get\$${name.slowToString()}";
+    return compiler.findInterceptor(new SourceString(mangledName));
   }
 
   Element getStaticSetInterceptor(SourceString name) {
-    String mangledName = "builtin\$set\$${name.slowToString()}";
-    return compiler.findHelper(new SourceString(mangledName));
+    String mangledName = "set\$${name.slowToString()}";
+    return compiler.findInterceptor(new SourceString(mangledName));
   }
 
   Element getOperatorInterceptor(Operator op) {
@@ -64,6 +73,7 @@ class Interceptors {
   }
 
   Element getBoolifiedVersionOf(Element interceptor) {
+    if (interceptor === null) return interceptor;
     String boolifiedName = "${interceptor.name.slowToString()}B";
     return compiler.findHelper(new SourceString(boolifiedName));
   }