Re-reland: Remove register index/code indirection

BUILD.gn

Index: BUILD.gn
diff --git a/BUILD.gn b/BUILD.gn
index 0191508fd8a69819474215f15709e03165e6543a..20e82d328dab4227a90fa740815dd4dbc6de0dbd 100644
--- a/BUILD.gn
+++ b/BUILD.gn
@@ -838,8 +838,6 @@ source_set("v8_base") {
     "src/compiler/register-allocator.h",
     "src/compiler/register-allocator-verifier.cc",
     "src/compiler/register-allocator-verifier.h",
-    "src/compiler/register-configuration.cc",
-    "src/compiler/register-configuration.h",
     "src/compiler/representation-change.h",
     "src/compiler/schedule.cc",
     "src/compiler/schedule.h",
@@ -1147,6 +1145,8 @@ source_set("v8_base") {
     "src/regexp/regexp-macro-assembler.h",
     "src/regexp/regexp-stack.cc",
     "src/regexp/regexp-stack.h",
+    "src/register-configuration.cc",
+    "src/register-configuration.h",
     "src/runtime-profiler.cc",
     "src/runtime-profiler.h",
     "src/runtime/runtime-array.cc",