[llvm] [CSSPGO] Fix redundant reading of profile metadata (PR #129609)

[Lei Wang via llvm-commits]

wlei-llvm wrote:

> > Fix a build speed regression due to repeated reading of profile metadata
> 
> @wlei-llvm when was the regression introduced?

The regression was triggered after we enabled the call-graph matching(https://github.com/llvm/llvm-project/pull/125938), it was initially introduced in https://github.com/llvm/llvm-project/pull/104654 when we refactored to support on-demand reading profiles(call-graph matching is the only usage for this feature).

https://github.com/llvm/llvm-project/pull/129609