PC Sampling: Disable coredump when sessions active

When doing a coredump, we try to park the wave and save its PC in
ttmp7/ttmp11, but these registers will be overwritten by PC Sampling
requests.

Change-Id: I60fb734eb3bed4ee3cc8d8bba9ec4a527fff9671

runtime/hsa-runtime/pcs/pcs_runtime.cpp

@@ -100,6 +100,10 @@ void PcsRuntime::DestroySingleton() {
 
 void ReleasePcSamplingRsrcs() { PcsRuntime::DestroySingleton(); }
 
+bool PcsRuntime::SessionsActive() const {
+  return pc_sampling_.size() > 0;
+}
+
 PcsRuntime::PcSamplingSession::PcSamplingSession(
     core::Agent* _agent, hsa_ven_amd_pcs_method_kind_t method, hsa_ven_amd_pcs_units_t units,
     size_t interval, size_t latency, size_t buffer_size,