When LLVM_PROFILE_FILE is set incorrectly (e.g. multiple %c) and it
falls back to use `default.profraw` name, but continuous mode is still
set. This might cause signal bus in the following scenario.
LLVM_PROFILE_FILE is set incorrectly (with "%c%c") for process A and B.
Suppose A starts first and falls back to use `default.profraw` and
mmaped its file content to memory. Later B starts and also falls back to
use `default.profraw`, but it will truncate the file because online
merging is disable when reseting to `default.profraw`. When A tries to
update counter via mmaped memory, signal bus will occur.
This fixes it by disabling continuous mode when reset to
default.profraw.
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