JIT: assert if we see schema mismatches with dynamic pgo data

When the profile data comes from dynamic PGO, the spanning tree encoded in the
schema produced by an earlier tier should exactly match the spanning tree for
the current jit attempt, since the JIT and method IL are identical.

(This is not the case for static PGO; that schema may have come from a different
JIT and/or different version of IL).

Note in release modes we won't assert; instead, we will silently throw the PGO
data away.

Follow-on change to dotnet#85805 to catch more issues like dotnet#85799.

src/coreclr/jit/fgprofile.cpp

@@ -3297,6 +3297,15 @@ void EfficientEdgeCountReconstructor::Prepare()
 //
 void EfficientEdgeCountReconstructor::Solve()
 {
+    // If we have dynamic PGO data, we don't expect to see any mismatches,
+    // since the schema we got from the runtime should have come from the
+    // exact same JIT and IL, created in an earlier tier.
+    //
+    if (m_comp->fgPgoSource == ICorJitInfo::PgoSource::Dynamic)
+    {
+        assert(!m_mismatch);
+    }
+
     // If issues arose earlier, then don't try solving.
     //
     if (m_badcode || m_mismatch || m_allWeightsZero)