LibJS: Cache Executable constants for asm Call

Mirror Executable's constants size and data pointer in adjacent fields
so the asm Call fast path can pair-load them together. The underlying
Vector layout keeps size and data apart, so a small cached raw span
lets the hot constant-copy loop fetch both pieces of metadata at once.

Libraries/LibJS/Bytecode/AsmInterpreter/asmint.asm

@@ -2139,8 +2139,7 @@ handler Call
 
 .copy_constants:
     load64 t0, [t2, EXECUTION_CONTEXT_EXECUTABLE]
-    load64 t3, [t0, EXECUTABLE_CONSTANTS_SIZE]
-    load64 t0, [t0, EXECUTABLE_CONSTANTS_DATA]
+    load_pair64 t3, t0, [t0, EXECUTABLE_ASM_CONSTANTS_SIZE], [t0, EXECUTABLE_ASM_CONSTANTS_DATA]
     mov t1, t5
     xor t8, t8
 .copy_constants_loop:

Libraries/LibJS/Bytecode/AsmInterpreter/gen_asm_offsets.cpp

@@ -132,6 +132,8 @@ int main()
     EMIT_OFFSET(EXECUTABLE_PROPERTY_LOOKUP_CACHES, Executable, property_lookup_caches);
     EMIT_OFFSET(EXECUTABLE_REGISTERS_AND_LOCALS_COUNT, Executable, registers_and_locals_count);
     EMIT_OFFSET(EXECUTABLE_REGISTERS_AND_LOCALS_AND_CONSTANTS_COUNT, Executable, registers_and_locals_and_constants_count);
+    EMIT_OFFSET(EXECUTABLE_ASM_CONSTANTS_SIZE, Executable, asm_constants_size);
+    EMIT_OFFSET(EXECUTABLE_ASM_CONSTANTS_DATA, Executable, asm_constants_data);
 
     // ExecutionContext layout
     outln("\n# ExecutionContext layout");

Libraries/LibJS/Bytecode/Executable.cpp

@@ -83,6 +83,8 @@ Executable::Executable(
     template_object_caches.resize(number_of_template_object_caches);
     object_shape_caches.resize(number_of_object_shape_caches);
     object_property_iterator_caches.resize(number_of_object_property_iterator_caches);
+    asm_constants_size = this->constants.size();
+    asm_constants_data = this->constants.data();
 }
 
 Executable::~Executable() = default;

Libraries/LibJS/Bytecode/Executable.h

@@ -193,6 +193,8 @@ public:
 
     u32 registers_and_locals_count { 0 };
     u32 registers_and_locals_and_constants_count { 0 };
+    size_t asm_constants_size { 0 };
+    Value const* asm_constants_data { nullptr };
 
     struct ExceptionHandlers {
         size_t start_offset;