Remove unused class member `art::OatFileAssistant::flock_`.

This was spotted while updating language to comply with Android's
inclusive language guidance, which affected the documentation of this
class member.
See https://source.android.com/setup/contribute/respectful-code for
reference.

Also remove the explicit definition of
`art::OatFileAssistant::~OatFileAssistant`, which is no longer needed.

#inclusivefixit

Test: Build ART and run ART tests
Bug: 161336379
Bug: 161896447
Change-Id: I30fed43be7b2bf78af5f2cca7e1e54ec0df159fb
diff --git a/runtime/oat_file_assistant.cc b/runtime/oat_file_assistant.cc
index de3d878..bda7b82 100644
--- a/runtime/oat_file_assistant.cc
+++ b/runtime/oat_file_assistant.cc
@@ -156,13 +156,6 @@
   }
 }
 
-OatFileAssistant::~OatFileAssistant() {
-  // Clean up the lock file.
-  if (flock_.get() != nullptr) {
-    unlink(flock_->GetPath().c_str());
-  }
-}
-
 bool OatFileAssistant::UseFdToReadFiles() {
   return zip_fd_ >= 0;
 }
diff --git a/runtime/oat_file_assistant.h b/runtime/oat_file_assistant.h
index 069e6fa..51f58ad 100644
--- a/runtime/oat_file_assistant.h
+++ b/runtime/oat_file_assistant.h
@@ -121,8 +121,6 @@
                    int oat_fd,
                    int zip_fd);
 
-  ~OatFileAssistant();
-
   // Returns true if the dex location refers to an element of the boot class
   // path.
   bool IsInBootClassPath();
@@ -400,11 +398,6 @@
   // Validates the boot class path checksum of an OatFile.
   bool ValidateBootClassPathChecksums(const OatFile& oat_file);
 
-  // To implement Lock(), we lock a dummy file where the oat file would go
-  // (adding ".flock" to the target file name) and retain the lock for the
-  // remaining lifetime of the OatFileAssistant object.
-  ScopedFlock flock_;
-
   std::string dex_location_;
 
   // Whether or not the parent directory of the dex file is writable.