Refactor: Simplify boolean conditional return statements in lib/Lex

[LegalizeAdulthood]

Summary

Use clang-tidy to simplify boolean conditional return statements

[dblaikie]

LGTM

[LegalizeAdulthood]

Update to latest.
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lib/Lex/PPDirectives.cpp

if (IdentifierInfo *II = Value.getIdentifierInfo()) {
       }
       return TrimmedValue.equals(MacroText);
     } else {
       return false;
     }
   }
 
   // #define inline
-  if (MacroName.isOneOf(tok::kw_extern, tok::kw_inline, tok::kw_static,
+  return MacroName.isOneOf(tok::kw_extern, tok::kw_inline, tok::kw_static,
                            tok::kw_const) &&
-      MI->getNumTokens() == 0) {
-    return true;
-  }
-
-  return false;
+         MI->getNumTokens() == 0;
 }
 
 /// HandleDefineDirective - Implements \#define.  This consumes the entire macro
 /// line then lets the caller lex the next real token.
 void Preprocessor::HandleDefineDirective(Token &DefineTok,
                                          bool ImmediatelyAfterHeaderGuard) {
   ++NumDefined;
 

lib/Lex/PPMacroExpansion.cpp

for (SmallVectorImpl<Token>::const_iterator I = Tokens.begin(),
     } else if (I->is(tok::l_brace)) {
       Brackets.push_back(Brace);
     } else if (I->is(tok::r_brace)) {
       if (Brackets.empty() || Brackets.back() == Paren)
         return false;
       Brackets.pop_back();
     }
   }
-  if (!Brackets.empty())
-    return false;
-  return true;
+  return Brackets.empty();
 }
 
 /// GenerateNewArgTokens - Returns true if OldTokens can be converted to a new
 /// vector of tokens in NewTokens.  The new number of arguments will be placed
 /// in NumArgs and the ranges which need to surrounded in parentheses will be
 /// in ParenHints.
 /// Returns false if the token stream cannot be changed.  If this is because
 /// of an initializer list starting a macro argument, the range of those