[Perf] (MG_Util): replace the builtin-shadowing string scans with one tokenize and a SPIR-V OpName pass

RenameBuiltinShadowingFunction probed the whole source ten times per compile
(5 names x mask + scan, each a full-text pass) and still had two blind spots:
a 5-name list and single-line-definition-only detection. On Complementary-scale
packs (4.5MB of sources) that was ~68% of the compile phase.

The rename is now split by FAILURE LAYER, both halves sharing one name table
header so they cannot drift:

- A SPIR-V OpName pass in SanitizeAndOptimizeBinary covers the full ESSL 3.20
  builtin set (~146 names). Renaming a function id is safe by construction:
  builtin calls are GLSL.std.450 instructions and can never resolve to a user
  OpFunction, overloads are distinct ids (a helper overload delegating to the
  real builtin keeps working), dead preprocessor branches never reach SPIR-V,
  and macro-expanded definitions are covered. ESSL 3.x is the only consumer
  that forbids the redefinitions, and this pass runs before its transpile.

- A lexical pass covers only the 5 names whose exact-signature redefinitions
  glslang's relaxed parse rejects outright (never producing SPIR-V for the
  backstop): the historical fma/max3/min3/round/tanh. One TokenizeCode pass;
  definition detection requires brace depth 0, a type-identifier previous
  token that is neither a statement keyword nor a directive tail, and skips
  files whose token-level braces do not balance (preprocessor-asymmetric
  arms) - over-detection is unrecoverable, so every ambiguity falls through
  to the backstop.

Measured on the compile phase (prefix-diff, 3-run medians, Espryt/NVIDIA):
complementary-reimagined 20.0s -> 5.5s, BSL 2.14s -> 1.85s. bliss (the pack
that ships from-scratch fma/tanh helpers) stays at SSIM 0.999962.

Tests: end-to-end ESSL assertions for the multiline-definition and
new-overload shapes, the three adversarial-review reproductions (statement-
keyword call under asymmetric braces, dead-#if compat shim, overload
delegating to the shadowed builtin), and a source-level assertion pinning
the lexical half specifically.

MobileGL/MG_Util/ShaderTranspiler/ShaderCompiler.cpp

@@ -15,6 +15,7 @@
 #include "SpirvPasses/EliminateFloatEqualsZeroPass.h"
 #include "SpirvPasses/FlattenInterfaceStructPass.h"
 #include "SpirvPasses/RenameSamplerFunctionParameterPass.h"
+#include "SpirvPasses/RenameBuiltinShadowingFunctionsPass.h"
 #include "SpirvPasses/DecomposeWorkgroupVec3Pass.h"
 #include "SpirvPasses/DecoratePositionInvariantPass.h"
 #include "SpirvPasses/LowerDrawParametersPass.h"
@@ -310,6 +311,8 @@ namespace MobileGL {
                 optimizer.RegisterPass(CreateRemoveUnusedInterfaceVariablesPass());
                 optimizer.RegisterPass(FlattenInterfaceStructPass::CreateFlattenInterfaceStructPass());
                 optimizer.RegisterPass(RenameSamplerFunctionParameterPass::CreateRenameSamplerFunctionParameterPass());
+                optimizer.RegisterPass(
+                    RenameBuiltinShadowingFunctionsPass::CreateRenameBuiltinShadowingFunctionsPass());
                 optimizer.RegisterPass(EliminateFloatEqualsZeroPass::CreateEliminateFloatEqualsZeroPass());
                 optimizer.RegisterPass(DecomposeWorkgroupVec3Pass::CreateDecomposeWorkgroupVec3Pass());