heap profiler: reporter doesn't convert the valid values in some cases

[yorkie]

• Version: master
• Platform: all
• Subsystem: heap profiler

The following cases are wrong when we load some heapdump at Chrome(76.0.3809.132):

• class doesn't has name
• primitives doesn't get correct value

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[yorkie]

Removed the "good first issue" label just like #558.