Delete IREE_BUILD_EXPERIMENTAL_MODEL_BUILDER config.

The Model-Builder sub-project was moved to a different repository.
diff --git a/CMakeLists.txt b/CMakeLists.txt
index bc71714..b2ec58f 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -86,7 +86,6 @@
 # Experimental project flags
 #-------------------------------------------------------------------------------
 
-option(IREE_BUILD_EXPERIMENTAL_MODEL_BUILDER "Builds experimental Model-Builder sub-project." OFF)
 option(IREE_BUILD_EXPERIMENTAL_REMOTING "Builds experimental remoting support." OFF)
 option(IREE_BUILD_EXPERIMENTAL_JAVA_BINDINGS "Builds the experimental java bindings." OFF)
 
@@ -94,7 +93,7 @@
 # Derived flags based on primary options
 #-------------------------------------------------------------------------------
 
-if(${IREE_BUILD_SAMPLES} OR ${IREE_BUILD_EXPERIMENTAL_MODEL_BUILDER})
+if(${IREE_BUILD_SAMPLES})
   set(IREE_BUILD_COMPILER ON CACHE BOOL "Build the IREE compiler for sample projects." FORCE)
 endif()
 
@@ -302,11 +301,6 @@
   # Stash cmake build type in case LLVM messes with it.
   set(_CMAKE_BUILD_TYPE "${CMAKE_BUILD_TYPE}")
 
-  # experimental model builder uses vulkan runner.
-  if(${IREE_BUILD_EXPERIMENTAL_MODEL_BUILDER})
-    set(MLIR_VULKAN_RUNNER_ENABLED ON)
-  endif()
-
   add_subdirectory("${llvm_monorepo_path}/llvm" "third_party/llvm-project/llvm" EXCLUDE_FROM_ALL)
 
   # Reset CMAKE_BUILD_TYPE to its previous setting.
@@ -479,10 +473,6 @@
   add_subdirectory(iree/samples/simple_embedding)
 endif()
 
-if(${IREE_BUILD_EXPERIMENTAL_MODEL_BUILDER})
-  add_subdirectory(experimental/ModelBuilder)
-endif()
-
 if(${IREE_BUILD_EXPERIMENTAL_REMOTING})
   # NOTE: Currently liburing is only used by the experimental remoting
   # support, so keeping it scoped here. If this broadens, then include along
diff --git a/docs/developers/get_started/cmake_options_and_variables.md b/docs/developers/get_started/cmake_options_and_variables.md
index 52c65f2..89606bf 100644
--- a/docs/developers/get_started/cmake_options_and_variables.md
+++ b/docs/developers/get_started/cmake_options_and_variables.md
@@ -64,10 +64,6 @@
 
 Builds the experimental java bindings. Defaults to `OFF`.
 
-#### `IREE_BUILD_EXPERIMENTAL_MODEL_BUILDER`:BOOL
-
-Builds the experimental model builder component. Defaults to `OFF`.
-
 #### `IREE_BUILD_EXPERIMENTAL_REMOTING`:BOOL
 
 Builds experimental remoting component. Defaults to `OFF`.