[compiler-rt][asan][hwasan] Fix Fuchsia build

Fix build failure in Fuchsia build from refactoring in
5d2be1a188

Guard the moved versions of ReserveShadowMemoryRange and ProtectGap
the same way they were in the asan code originally (not for Fuchsia or
RTEMS). Otherwise we end up with unsats as they invoke functions not
defined there.

compiler-rt/lib/sanitizer_common/sanitizer_common_libcdep.cpp

@@ -139,6 +139,8 @@ uptr ReservedAddressRange::InitAligned(uptr size, uptr align,
   return start;
 }
 
+#if !SANITIZER_FUCHSIA && !SANITIZER_RTEMS
+
 // Reserve memory range [beg, end].
 // We need to use inclusive range because end+1 may not be representable.
 void ReserveShadowMemoryRange(uptr beg, uptr end, const char *name,
@@ -188,6 +190,8 @@ void ProtectGap(uptr addr, uptr size, uptr zero_base_shadow_start,
   Die();
 }
 
+#endif  // !SANITIZER_FUCHSIA && !SANITIZER_RTEMS
+
 }  // namespace __sanitizer
 
 SANITIZER_INTERFACE_WEAK_DEF(void, __sanitizer_sandbox_on_notify,