Don't allow read truncation or appending for file operations.

If a caller attempts to read a file with the truncation or append
bits and doesn't specify the write bit as well, silently drop the
invalid bits to prevent unintended changes.

Bug: 414387646
Test: atest CtsContentProviderTestCases
Flag: EXEMPT security fix
Change-Id: I1a8993d99d1f381e1122b304d223a5c10e4578ce