Remove Cargo's internal hamcrest module

[dwijnand]

Fixes #5742

[rust-highfive]

r? @matklad

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[ehuss]

Would you mind updating the docs?

cargo/tests/testsuite/support/mod.rs

Lines 21 to 22 in a49589c

	To run cargo, call the `cargo` method and use the `hamcrest` matchers to check
	the output.

cargo/tests/testsuite/support/mod.rs

Lines 45 to 47 in a49589c

	See the `hamcrest` module for other matchers like
	`is_not(existing_file(path))`. This is not the actual hamcrest library, but
	instead a lightweight subset of matchers that are used in cargo tests.

[alexcrichton]

@bors: r+

😲

[bors]

📌 Commit a88a637 has been approved by alexcrichton

[bors]

⌛ Testing commit a88a637 with merge b1209f8...

[bors]

☀️ Test successful - status-appveyor, status-travis
Approved by: alexcrichton
Pushing b1209f8 to master...