Fixing the intermittent Helix tool test failure

[jsjtzyy]

The replica size is changed in testEverything() method. If new replica
from initial partition is added to new node disk and is not reset when
calling writeBootstrapOrUpgrade(), then the second time it is invoked,
validating cluster manager in Helix tool would see different size of
replica of same partition and fails the test.
This patch ensures that if new replica is from initial partition, the
replica is only allowed to be added to original nodes in HardwareLayout,
which would be reset by writeBootstrapOrUpgrade() and avoid inconsistent
replica size error in validating cluster manager.

[codecov-io]

Codecov Report

Merging #1162 into master will decrease coverage by 0.06%.
The diff coverage is n/a.

@@             Coverage Diff              @@
##             master    #1162      +/-   ##
============================================
- Coverage     69.81%   69.75%   -0.07%     
+ Complexity     5312     5310       -2     
============================================
  Files           420      420              
  Lines         32547    32547              
  Branches       4139     4139              
============================================
- Hits          22724    22703      -21     
- Misses         8700     8711      +11     
- Partials       1123     1133      +10

Impacted Files	Coverage Δ	Complexity Δ
...java/com.github.ambry.store/CompactionManager.java	87.33% <0%> (-3.34%)	19% <0%> (ø)
...github.ambry.rest/AsyncRequestResponseHandler.java	88.59% <0%> (-2.29%)	23% <0%> (ø)
...b.ambry.network/BlockingChannelConnectionPool.java	70.17% <0%> (-1.76%)	9% <0%> (ø)
...in/java/com.github.ambry.store/BlobStoreStats.java	70.92% <0%> (-1.04%)	103% <0%> (-1%)
...src/main/java/com.github.ambry.commons/BlobId.java	93.18% <0%> (-0.36%)	71% <0%> (-1%)
...java/com.github.ambry.network/SSLTransmission.java	69.42% <0%> (-0.32%)	68% <0%> (-1%)
...ain/java/com.github.ambry.router/PutOperation.java	90.86% <0%> (ø)	107% <0%> (ø)	⬇️
.../java/com.github.ambry.router/DeleteOperation.java	93.61% <0%> (+1.41%)	48% <0%> (+1%)	⬆️

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[pnarayanan]

Collections.unmodifiable?