Coverity scan reported new defects related to jhinplace.cpp

 *** CID 1536705:    (DEADCODE)
/home/centos/build/CE/platform/HPCC-Platform/system/jhtree/jhinplace.cpp: 2046 in CInplaceLeafWriteNode::write(IFileIOStream *, CRC32 *)()
2040             }
2041
2042             if (keyLen != keyCompareLen)
2043             {
2044                 if (useUncompressed)
2045                 {
>>>     CID 1536705:    (DEADCODE)
>>>     Execution cannot reach this statement: "if (this->isVariable)
  ser...".
2046                     if (isVariable)
2047                         serializePacked(data, uncompressed.length());
2048                     data.append(uncompressed.length(), uncompressed.bufferBase());
2049                 }
2050                 else
2051                 {
/home/centos/build/CE/platform/HPCC-Platform/system/jhtree/jhinplace.cpp: 2023 in CInplaceLeafWriteNode::write(IFileIOStream *, CRC32 *)()
2017             //Pack these by scaling and reducing the number of bytes
2018             unsigned bytesPerPosition = 0;
2019             if (minPosition != maxPosition)
2020                 bytesPerPosition = bytesRequired(maxPosition-minPosition);
2021
2022             bool useUncompressed = false; // Implement in HPCC-19115
>>>     CID 1536705:    (DEADCODE)
>>>     Execution cannot reach the expression "64" inside this statement: "sizeMask = (byte)bytesPerPo...".
2023             byte sizeMask = (byte)bytesPerPosition | (useUncompressed ? NSFuncompressedPayload : 0);
2024             data.append(sizeMask);
2025             serializePacked(data, minPosition);
2026             if (bytesPerPosition != 0)
2027             {
2028                 for (unsigned i=0; i < positions.ordinality(); i++)** CID 1536704:  Performance inefficiencies  (PASS_BY_VALUE)
/home/centos/build/CE/platform/HPCC-Platform/system/jhtree/jhinplace.cpp: 2227 in InplaceIndexTest::testSearching()::[lambda(const char *) (instance 2)]::operator ()(const char *) const()
________________________________________________________________________________________________________
*** CID 1536704:  Performance inefficiencies  (PASS_BY_VALUE)
/home/centos/build/CE/platform/HPCC-Platform/system/jhtree/jhinplace.cpp: 2227 in InplaceIndexTest::testSearching()::[lambda(const char *) (instance 2)]::operator ()(const char *) const()
2221
2222                 if (!searcher.getValueAt(i, result))
2223                     printf("%u: getValue() failed\n", i);
2224                 else if (!streq(entry, result))
2225                     printf("%u: '%s', '%s'\n", i, entry, result);
2226
>>>     CID 1536704:  Performance inefficiencies  (PASS_BY_VALUE)
>>>     Capturing variable "entries", which is a C-array, in a lambda.  Unlike function parameters, this array is copied and passed by value.
2227                 auto callback = [numEntries, entries, &searcher](const char * search)
2228                 {
2229                     for (unsigned j= 0; j < numEntries; j++)
2230                     {
2231                         int expected = normalizeCompare(strcmp(search, entries[j]));
2232                         int actual = normalizeCompare(searcher.compareValueAt(search, j));** CID 1536703:  Null pointer dereferences  (FORWARD_NULL)
/home/centos/build/CE/platform/HPCC-Platform/testing/unittests/datamaskingtests.cpp: 730 in DataMaskingEngineTests::assertQueriedProfile(DataMasking::CEngine *, const char *, unsigned char, const char *, unsigned char)()
________________________________________________________________________________________________________
*** CID 1536702:  Memory - illegal accesses  (NO_EFFECT)
/home/centos/build/CE/platform/HPCC-Platform/system/jhtree/jhtree.cpp: 3445 in IKeyManagerTest::buildTestKey(const char *, bool, bool, bool, bool, bool, IOutputMetaData *, const char *)()
3439                     (useTrailingHeader ? USE_TRAILING_HEADER : 0) |
3440                     (noSeek ? TRAILING_HEADER_ONLY : 0) |
3441                     0,
3442                     maxRecSize, NODESIZE, keyedSize, 0, &helper, true, false);
3443
3444             char keybuf[18];
>>>     CID 1536702:  Memory - illegal accesses  (NO_EFFECT)
>>>     Function "memset" with fill value "'0'" (the zero character) in "memset(keybuf, 48, 18UL)".
3445             memset(keybuf, '0', 18);
3446             uint32_t maxRecordSizeSeen = 0;
3447             for (unsigned count = 0; count < 10000; count++)
3448             {
3449                 unsigned datasize = 10;
3450                 if (variable && (count % 10)==0)