[AutoDiff] Remove flaky SR-12650 negative test.

[dan-zheng]

@noDerivative parameter mangling was added in #31201, so the negative test is not meaningful.

The test occasionally flaked during CI, so it's better to remove it:

14:20:50 FAIL: Swift(linux-x86_64) :: AutoDiff/compiler_crashers_fixed/sr12650-noderivative-parameter-type-mangling.swift (13232 of 13264)
14:20:50 ******************** TEST 'Swift(linux-x86_64) :: AutoDiff/compiler_crashers_fixed/sr12650-noderivative-parameter-type-mangling.swift' FAILED ********************
14:20:50 Script:
14:20:50 --
14:20:50 : 'RUN: at line 1';   /home/buildnode/jenkins/workspace/swift-PR-Linux-smoke-test@2/branch-master/buildbot_linux/swift-linux-x86_64/bin/swiftc -target x86_64-unknown-linux-gnu -toolchain-stdlib-rpath  -module-cache-path '/home/buildnode/jenkins/workspace/swift-PR-Linux-smoke-test@2/branch-master/buildbot_linux/swift-linux-x86_64/swift-test-results/x86_64-unknown-linux-gnu/clang-module-cache' -swift-version 4  -Xfrontend -ignore-module-source-info  -g /home/buildnode/jenkins/workspace/swift-PR-Linux-smoke-test@2/branch-master/swift/test/AutoDiff/compiler_crashers_fixed/sr12650-noderivative-parameter-type-mangling.swift
14:20:50 --
14:20:50 Exit Code: 254
14:20:50 
14:20:50 Command Output (stderr):
14:20:50 --
14:20:50 
clang-10: error: unable to execute command: Bus error (core dumped)
14:20:50 clang-10: error: linker command failed due to signal (use -v to see invocation)
14:20:50 <unknown>:0: error: link command failed with exit code 254 (use -v to see invocation)

[dan-zheng]

@swift-ci Please smoke test