Revert "[InlineCost] Enable the cost benefit analysis on FDO"

This reverts commit ef69aa9.
Makes clang assert in PGO builds, see repro tgz in
https://bugs.chromium.org/p/chromium/issues/detail?id=1192783#c6

Author: nico

llvm/lib/Analysis/InlineCost.cpp

@@ -675,22 +675,15 @@ class InlineCostCallAnalyzer final : public CallAnalyzer {
   }
 
   bool isCostBenefitAnalysisEnabled() {
+    if (!InlineEnableCostBenefitAnalysis)
+      return false;
+
     if (!PSI || !PSI->hasProfileSummary())
       return false;
 
     if (!GetBFI)
       return false;
 
-    if (InlineEnableCostBenefitAnalysis.getNumOccurrences()) {
-      // Honor the explicit request from the user.
-      if (!InlineEnableCostBenefitAnalysis)
-        return false;
-    } else {
-      // Otherwise, require instrumentation profile.
-      if (!PSI->hasInstrumentationProfile())
-        return false;
-    }
-
     auto *Caller = CandidateCall.getParent()->getParent();
     if (!Caller->getEntryCount())
       return false;