Refactor quic_enable_version flags

In order to support our goal of enabling some QUIC versions with TLS on the GFE, we want to be able to enable some of them but not others. This CL refactors our flag code in order to do that. It also adds quic_disable_version flags for all existing versions to allow us to disable some versions on demand.

gfe-relnote: refactor never-enabled reloadable quic_enable_version flags

NO_BUG=refactor

emadomara@ please review //communication/synapse/networking/measuring_uploader/quic_uploader_client.cc
rch@ please review everything else :-)

PiperOrigin-RevId: 284641206
Change-Id: I9c5c8829fc8757b8ed3d6bd46689f9adafcb555a
diff --git a/quic/core/quic_version_manager.h b/quic/core/quic_version_manager.h
index e66e01f..b7aff69 100644
--- a/quic/core/quic_version_manager.h
+++ b/quic/core/quic_version_manager.h
@@ -41,10 +41,22 @@
 
  private:
   // Cached value of reloadable flags.
-  // quic_enable_version_99 flag
-  bool enable_version_99_;
-  // quic_supports_tls_handshake flag
-  bool enable_tls_;
+  // quic_enable_version_q099 flag
+  bool enable_version_q099_;
+  // quic_enable_version_t099 flag
+  bool enable_version_t099_;
+  // quic_disable_version_q050 flag
+  bool disable_version_q050_;
+  // quic_enable_version_t050 flag
+  bool enable_version_t050_;
+  // quic_disable_version_q049 flag
+  bool disable_version_q049_;
+  // quic_disable_version_q048 flag
+  bool disable_version_q048_;
+  // quic_disable_version_q046 flag
+  bool disable_version_q046_;
+  // quic_disable_version_q043 flag
+  bool disable_version_q043_;
 
   // The list of versions that may be supported.
   ParsedQuicVersionVector allowed_supported_versions_;