[K/N] Add flag to disable allocator overhead estimate

kotlin-native/runtime/src/alloc/custom/cpp/AllocatorImpl.cpp

@@ -52,6 +52,7 @@ void alloc::Allocator::clearForTests() noexcept {
 }
 
 size_t alloc::Allocator::estimateOverheadPerThread() noexcept {
+    if (compiler::disableAllocatorOverheadEstimate()) return 0;
     return impl_->heap().EstimateOverheadPerThread();
 }
 

kotlin-native/runtime/src/main/cpp/CompilerConstants.hpp

@@ -25,6 +25,7 @@
 extern "C" const int32_t Kotlin_needDebugInfo;
 extern "C" const int32_t Kotlin_runtimeAssertsMode;
 extern "C" const int32_t Kotlin_disableMmap;
+extern "C" const int32_t Kotlin_disableAllocatorOverheadEstimate;
 extern "C" const char* const Kotlin_runtimeLogs;
 extern "C" const int32_t Kotlin_concurrentWeakSweep;
 extern "C" const int32_t Kotlin_gcMarkSingleThreaded;
@@ -77,6 +78,10 @@ ALWAYS_INLINE inline bool disableMmap() noexcept {
     return Kotlin_disableMmap != 0;
 }
 
+ALWAYS_INLINE inline bool disableAllocatorOverheadEstimate() noexcept {
+    return Kotlin_disableAllocatorOverheadEstimate != 0;
+}
+
 ALWAYS_INLINE inline std::string_view runtimeLogs() noexcept {
     return Kotlin_runtimeLogs == nullptr ? std::string_view() : std::string_view(Kotlin_runtimeLogs);
 }

kotlin-native/runtime/src/test_support/cpp/CompilerGenerated.cpp

@@ -73,6 +73,7 @@ extern const int32_t Kotlin_disableMmap = 1;
 #else
 extern const int32_t Kotlin_disableMmap = 0;
 #endif
+extern const int32_t Kotlin_disableAllocatorOverheadEstimate = 0;
 extern const char* const Kotlin_runtimeLogs = nullptr;
 extern const int32_t Kotlin_concurrentWeakSweep = 1;
 #if KONAN_WINDOWS