JIT: run instrumentation phase just after importing (#47476)

As a prerequisite to enabling efficient instrumentation, add instrumentation
immediately after importing, so the flow graph more closely reflects the IL
level view.

Author: AndyAyersMS

src/coreclr/jit/compiler.cpp

@@ -4420,6 +4420,13 @@ void Compiler::compCompile(void** methodCodePtr, ULONG* methodCodeSize, JitFlags
     //
     DoPhase(this, PHASE_IMPORTATION, &Compiler::fgImport);
 
+    // If instrumenting, add block and class probes.
+    //
+    if (compileFlags->IsSet(JitFlags::JIT_FLAG_BBINSTR))
+    {
+        DoPhase(this, PHASE_IBCINSTR, &Compiler::fgInstrumentMethod);
+    }
+
     // Transform indirect calls that require control flow expansion.
     //
     DoPhase(this, PHASE_INDXCALL, &Compiler::fgTransformIndirectCalls);
@@ -4494,11 +4501,6 @@ void Compiler::compCompile(void** methodCodePtr, ULONG* methodCodeSize, JitFlags
     fgRemoveEH();
 #endif // !FEATURE_EH
 
-    if (compileFlags->IsSet(JitFlags::JIT_FLAG_BBINSTR))
-    {
-        DoPhase(this, PHASE_IBCINSTR, &Compiler::fgInstrumentMethod);
-    }
-
     // We could allow ESP frames. Just need to reserve space for
     // pushing EBP if the method becomes an EBP-frame after an edit.
     // Note that requiring a EBP Frame disallows double alignment.  Thus if we change this