Vendor valgrind headers

This is encouraged according to https://valgrind.org/docs/manual/manual-core-adv.html#manual-core-adv.clientreq

Internal.h

@@ -18,10 +18,7 @@
 #include <utility>
 #include <vector>
 
-#if __has_include(<valgrind/callgrind.h>)
-#define CALLGRIND
 #include <valgrind/callgrind.h>
-#endif
 
 #define DEBUG_VERBOSE 0
 
@@ -562,13 +559,10 @@ template <class ConflictSetImpl> struct TestDriver {
       assert(iter == keys.end());
       assert(i == numPointWrites + numRangeWrites);
 
-#ifdef CALLGRIND
       CALLGRIND_START_INSTRUMENTATION;
-#endif
       cs.addWrites(writes, numPointWrites + numRangeWrites);
-#ifdef CALLGRIND
       CALLGRIND_STOP_INSTRUMENTATION;
-#endif
+
       refImpl.addWrites(writes, numPointWrites + numRangeWrites);
 
       oldestVersion = std::max<int64_t>(writeVersion - arbitrary.bounded(10),
@@ -635,13 +629,11 @@ template <class ConflictSetImpl> struct TestDriver {
           new (arena) ConflictSet::Result[numPointReads + numRangeReads];
       auto *results2 =
           new (arena) ConflictSet::Result[numPointReads + numRangeReads];
-#ifdef CALLGRIND
+
       CALLGRIND_START_INSTRUMENTATION;
-#endif
       cs.check(reads, results1, numPointReads + numRangeReads);
-#ifdef CALLGRIND
       CALLGRIND_STOP_INSTRUMENTATION;
-#endif
+
       refImpl.check(reads, results2, numPointReads + numRangeReads);
       for (int i = 0; i < numPointReads + numRangeReads; ++i) {
         if (results1[i] != results2[i]) {