Revert "Add length-equality test in String operator== checks."

This reverts commit e28210d401ae4ed1258b84c9b17a172a757190e8.
diff --git a/include/utils/String8.h b/include/utils/String8.h
index a129222..cef8eca 100644
--- a/include/utils/String8.h
+++ b/include/utils/String8.h
@@ -418,9 +418,7 @@
 
 inline bool String8::operator==(const String8& other) const
 {
-    return (SharedBuffer::sizeFromData(mString) ==
-            SharedBuffer::sizeFromData(other.mString)) &&
-        strcmp(mString, other.mString) == 0;
+    return strcmp(mString, other.mString) == 0;
 }
 
 inline bool String8::operator!=(const String8& other) const