refactor: make hash random

[peter-jerry-ye]

This PR makes the hash seed random on JavaScript backend, and cleanup the relevant tests.

This PR is broken into two steps:

1. Migrate key.hash() to Hasher::new()..combine(key).finalize(). This is to make sure that the hash values are computed based on the hash combine with a seed, which is fixed at this stage. The tests based on the specific hash values are cleaned up.
2. Make the seed in Hasher::new() random for JS backend. It will use crypto.getRandomValue if possible, and fallback to Math.random. The tests based on the fixed hash computations are cleaned up.

[peter-jerry-ye]

Hasher::new() -> key.hash

remove impl hash

[coveralls]

Pull Request Test Coverage Report for Build 1429

Details

• 12 of 13 (92.31%) changed or added relevant lines in 6 files are covered.
• 18 unchanged lines in 4 files lost coverage.
• Overall coverage decreased (-0.2%) to 89.198%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
builtin/hasher.mbt	0	1	0.0%

Files with Coverage Reduction	New Missed Lines	%
immut/internal/sparse_array/sparse_array.mbt	1	94.19%
hashmap/json.mbt	3	0.0%
hashmap/utils.mbt	6	87.93%
hashset/hashset.mbt	8	88.14%

Totals
Change from base Build 1424:	-0.2%
Covered Lines:	9265
Relevant Lines:	10387

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💛 - Coveralls

[peter-jerry-ye]

@quake Would you like to review this PR?

[quake]

@quake Would you like to review this PR?

LGTM