`-DRT_SUPPORT_SANITIZERS=ON` changes runtime ABI

[JohanEngelen]

The runtime ABI should not change for compilation with -d-version=SupportSanitizers, yet it does because of:

ldc/runtime/druntime/src/core/thread/fiber.d

Line 554 in a49db8e

version (SupportSanitizers) version = CheckFiberMigration;

and

ldc/runtime/druntime/src/core/thread/fiber.d

Lines 1169 to 1172 in a49db8e

	version (CheckFiberMigration)
	{
	bool m_allowMigration;
	}