Use size_t for Process offset values #4684

Job	Run time
build-ubuntu-latest-minimal-gcc	37s
build-ubuntu-latest-minimal-clang	1m 5s
build-ubuntu-latest-full-featured-gcc	1m 10s
build-ubuntu-latest-gcc-static	52s
build-freebsd-latest-clang	6m 28s
build-macos-latest-clang	41s
build-dragonflybsd-latest-gcc	2m 21s
build-netbsd-latest-gcc	2m 45s
build-openbsd-latest-clang	2m 17s
build-ubuntu-latest-clang-analyzer	1m 17s
build-ubuntu-latest-clang-sanitizer	3m 21s
build-ubuntu-latest-full-featured-clang	1m 7s
build-ubuntu-latest-pcp	35s
lint-pcp-config	2s
lint-whitespace	2s
build-solaris-latest-gcc	3m 27s
	28m 7s

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