Remove reference to removed tests

Tests/LinuxMain.swift

@@ -1,10 +1,8 @@
 import XCTest
 
 import CryptoSwiftTests
-import TestsPerformance
 
 var tests = [XCTestCaseEntry]()
 tests += CryptoSwiftTests.__allTests()
-tests += TestsPerformance.__allTests()
 
 XCTMain(tests)