add a separate env variable HEAP_DUMP_DIR to set the heap dump path

[liaodn]

Fixes #172

add a separate env variable (say HEAP_DUMP_DIR, defaulting to LOG_DIR) to set the heap dump path

[coveralls]

Pull Request Test Coverage Report for Build 17284649121

Details

• 0 of 0 changed or added relevant lines in 0 files are covered.
• 42 unchanged lines in 10 files lost coverage.
• Overall coverage decreased (-0.06%) to 63.303%

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Files with Coverage Reduction	New Missed Lines	%
org/apache/bifromq/basecluster/transport/TCPTransport.java	1	87.06%
org/apache/bifromq/basekv/store/wal/KVRangeWAL.java	1	93.33%
org/apache/bifromq/basekv/store/wal/KVRangeWALSubscription.java	1	95.31%
org/apache/bifromq/basekv/raft/exception/InternalError.java	2	0.0%
org/apache/bifromq/basekv/store/range/KVRange.java	2	93.75%
org/apache/bifromq/basekv/store/range/KVRangeWriter.java	2	75.0%
org/apache/bifromq/basekv/raft/RaftNode.java	3	83.52%
org/apache/bifromq/basekv/store/range/LoadRecordableKVRangeWriter.java	4	66.67%
org/apache/bifromq/basecluster/memberlist/AutoDropper.java	7	80.34%
org/apache/bifromq/basekv/store/range/KVRangeFSM.java	19	73.83%

Totals
Change from base Build 17038586456:	-0.06%
Covered Lines:	23755
Relevant Lines:	36251

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💛 - Coveralls