[stable] Tests: Make fail_compilation/failexpression{3,4}.d work for targets with 64-bit real

[kinke]

The tested type combinations were trimmed with static if statements, causing real to effectively not be tested at all unless its size is 64 bits, then making the test fail because of the extra output.

Make these 2 tests target-agnostic by simply testing all combinations.

[dlang-bot]

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