Add more IME show/hide test cases to cover different flag settings(window flags, soft input mode flags), show/hide methods (from auto-show/IMM/WIC/Click), call times and user actions.
Merge the two TestActivitys in AutoShowTest and ImeOpenCloseStressTest into one in ImeStressTestUtil.
Modify test type in TEST_MAPPING to "presubmit-large" to avoid timeout.
See go/imf-test-cases for clearer test descriptions and results.
Bug: 242838873
Bug: 240359838
Test: atest com.android.inputmethod.stresstest.AutoShowTest
atest com.android.inputmethod.stresstest.ImeOpenCloseStressTest
Change-Id: Ibff3a85fa5b66c692a2fe8cd69fb1ca521b1b8d8
19e01a7c8b