Remove get_dbg_loc from DebugInfoBuilderMethods

It is only used within cg_llvm.

compiler/rustc_codegen_ssa/src/traits/debuginfo.rs

@@ -81,7 +81,6 @@ pub trait DebugInfoBuilderMethods: BackendTypes {
     );
     fn set_dbg_loc(&mut self, dbg_loc: Self::DILocation);
     fn clear_dbg_loc(&mut self);
-    fn get_dbg_loc(&self) -> Option<Self::DILocation>;
     fn insert_reference_to_gdb_debug_scripts_section_global(&mut self);
     fn set_var_name(&mut self, value: Self::Value, name: &str);
 }