Revert of Internalize strings in-place

src/runtime/runtime-i18n.cc

Index: src/runtime/runtime-i18n.cc
diff --git a/src/runtime/runtime-i18n.cc b/src/runtime/runtime-i18n.cc
index 82a78c68d65278b444ccaa0d2aa3e7b6d7afbf8d..f6f526ded289086460bc912a94f5bb12cec10142 100644
--- a/src/runtime/runtime-i18n.cc
+++ b/src/runtime/runtime-i18n.cc
@@ -885,8 +885,6 @@
   Handle<SeqTwoByteString> result;
   std::unique_ptr<uc16[]> sap;
 
-  if (dest_length == 0) return isolate->heap()->empty_string();
-
   // This is not a real loop. It'll be executed only once (no overflow) or
   // twice (overflow).
   for (int i = 0; i < 2; ++i) {
@@ -1108,7 +1106,7 @@
   int32_t length = s->length();
   s = String::Flatten(s);
 
-  if (s->HasOnlyOneByteChars() && length > 0) {
+  if (s->HasOnlyOneByteChars()) {
     Handle<SeqOneByteString> result =
         isolate->factory()->NewRawOneByteString(length).ToHandleChecked();