romio: fix weak symbol blocks for large count functions

[hzhou]

Pull Request Description

The weak symbol block has to be placed before inclusion of mpioprof.h.

The fixes the clang build errors introduced by #5278

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[hzhou]

test:mpich/ch3/tcp
compiler: clang

[hzhou]

test:mpich/ch3/tcp
compiler:clang

Solaris doesn't have clang configured.

[hzhou]

test:mpich/ch4/most
test:mpich/ch3/most