Fix WaitForLoadingSymbolsAndCheckModule (#3839)
Fix WaitForLoadingSymbolsAndCheckModule (#3839)

WaitForLoadingSymbolsAndCheckModule now correctly executes
WaitForLoadingSymbolsAndVerifyCache (before, it was just constructing
the class without calling execute()).

Also clean up the methods to wait for symbol loading. There are now using
the loading states indicated in the module table instead of trying to guess
the state from the status bar, which should make the tests a lot more stable.

Bug: b/237091604
google/orbit,google/orbit,google/orbit,google/orbit