Arm backend: Refactor compile spec handling (Try 2) (pytorch#14191)

Summary:
Pull Request resolved: pytorch#14191

Redoing pytorch#14111 with additional fixes

Differential Revision: D82171193

Author: mergennachin

backends/arm/TARGETS

@@ -14,7 +14,9 @@ python_library(
         "ethosu/partitioner.py"
     ],
     deps = [
-        ":arm_partitioner",
+        ":arm_vela",
+        ":ethosu_compile_spec",
+        "//executorch/backends/arm/tosa:partitioner",
     ]
 )
 python_library(
@@ -25,7 +27,8 @@ python_library(
         "vgf/partitioner.py"
     ],
     deps = [
-        ":arm_partitioner",
+        ":vgf_compile_spec",
+        "//executorch/backends/arm/tosa:partitioner",
     ]
 )
 python_library(
@@ -50,25 +53,11 @@ python_library(
         "//executorch/exir:lib",
     ],
 )
+
 python_library(
-    name = "arm_partitioner",
-    srcs = [
-        "tosa/backend.py",
-        "tosa/partitioner.py",
-    ],
-    deps = [
-        ":arm_backend",
-        ":constants",
-        "//executorch/backends/arm/debug:schema",
-        "//executorch/backends/arm/operator_support:operator_support",
-        "//executorch/backends/arm/_passes:passes",
-        "//executorch/exir:lib",
-    ],
-)
-python_library(
-    name = "arm_backend",
+    name = "arm_compile_spec",
     srcs = [
-        "arm_backend.py",
+        "common/arm_compile_spec.py",
     ],
     deps = [
         "fbsource//third-party/pypi/flatbuffers:flatbuffers",
@@ -79,11 +68,49 @@ python_library(
         "fbsource//third-party/tosa_tools/v1.00/serialization_lib/python/tosa:tosa",
         ":arm_vela",
         ":process_node",
+        "//executorch/exir/backend:compile_spec_schema",
         "//executorch/backends/arm/operators:lib",
         "//executorch/backends/arm/operators:node_visitor",
         "//executorch/backends/arm/_passes:passes",
     ],
 )
+
+python_library(
+    name = "ethosu_compile_spec",
+    srcs = [
+        "ethos/__init__.py",
+        "ethosu/compile_spec.py",
+    ],
+    deps = [
+        ":arm_compile_spec",
+        "//executorch/backends/arm/tosa:specification",
+    ],
+)
+
+python_library(
+    name = "tosa_compile_spec",
+    srcs = [
+        "tosa/__init__.py",
+        "tosa/compile_spec.py",
+    ],
+    deps = [
+        ":arm_compile_spec",
+        "//executorch/backends/arm/tosa:specification",
+    ],
+)
+
+python_library(
+    name = "vgf_compile_spec",
+    srcs = [
+        "vgf/__init__.py",
+        "vgf/compile_spec.py",
+    ],
+    deps = [
+        ":arm_compile_spec",
+        "//executorch/backends/arm/tosa:specification",
+    ],
+)
+
 python_library(
     name = "process_node",
     srcs = ["process_node.py"],