[wasm][refactor] Move ModuleDecoderImpl to -impl.h

Ctrl+X, Ctrl+V. No change in behavior.
This is a preparational step for templatizing the module decoder
for disassembler purposes.

Bug: v8:12917
Change-Id: I08a5d2e666cd16a207e9862b2691446c0473ddb0
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3738221
Auto-Submit: Jakob Kummerow <jkummerow@chromium.org>
Reviewed-by: Manos Koukoutos <manoskouk@chromium.org>
Commit-Queue: Jakob Kummerow <jkummerow@chromium.org>
Cr-Commit-Position: refs/heads/main@{#81489}

BUILD.bazel

@@ -2511,6 +2511,7 @@ filegroup(
             "src/wasm/module-compiler.h",
             "src/wasm/module-decoder.cc",
             "src/wasm/module-decoder.h",
+            "src/wasm/module-decoder-impl.h",
             "src/wasm/module-instantiate.cc",
             "src/wasm/module-instantiate.h",
             "src/wasm/names-provider.cc",

BUILD.gn

@@ -3615,6 +3615,7 @@ v8_header_set("v8_internal_headers") {
       "src/wasm/memory-protection-key.h",
       "src/wasm/memory-tracing.h",
       "src/wasm/module-compiler.h",
+      "src/wasm/module-decoder-impl.h",
       "src/wasm/module-decoder.h",
       "src/wasm/module-instantiate.h",
       "src/wasm/names-provider.h",

tools/generate-header-include-checks.py

@@ -29,12 +29,17 @@ MY_DIR = os.path.dirname(os.path.realpath(__file__))
 V8_DIR = os.path.dirname(MY_DIR)
 OUT_DIR = os.path.join(V8_DIR, 'check-header-includes')
 AUTO_EXCLUDE = [
-  # flag-definitions.h needs a mode set for being included.
-  'src/flags/flag-definitions.h',
-  # recorder.h should only be included conditionally.
-  'src/libplatform/tracing/recorder.h',
-  # trap-handler-simulator.h can only be included in simulator builds.
-  'src/trap-handler/trap-handler-simulator.h',
+    # flag-definitions.h needs a mode set for being included.
+    'src/flags/flag-definitions.h',
+    # recorder.h should only be included conditionally.
+    'src/libplatform/tracing/recorder.h',
+    # trap-handler-simulator.h can only be included in simulator builds.
+    'src/trap-handler/trap-handler-simulator.h',
+    # The src/wasm/*-impl.h coding pattern is generally at odds with the rule
+    # being enforced here: they are meant to provide possibly-incomplete
+    # templates, and their users must provide their prerequisites.
+    'src/wasm/function-body-decoder-impl.h',
+    'src/wasm/module-decoder-impl.h',
 ]
 AUTO_EXCLUDE_PATTERNS = [
     'src/base/atomicops_internals_.*',