testsuite: move handle-multiline-outputs to before check for blank lines

testsuite: move handle-multiline-outputs to before check for blank lines

I have followup patches that require checking for multiline patterns
that have blank lines within them, so this moves the handling of
multiline patterns before the check for blank lines, allowing for such
multiline patterns.

Doing so uncovers some issues with existing multiline directives, which
the patch fixes.

gcc/testsuite/ChangeLog:
	* c-c++-common/Wlogical-not-parentheses-2.c: Split up the
	multiline directive.
	* gcc.dg/analyzer/malloc-macro-inline-events.c: Remove redundant
	dg-regexp directives.
	* gcc.dg/missing-header-fixit-5.c: Split up the multiline
	directives.
	* lib/gcc-dg.exp (gcc-dg-prune): Move call to
	handle-multiline-outputs from prune_gcc_output to here.
	* lib/multiline.exp (dg-end-multiline-output): Move call to
	maybe-handle-nn-line-numbers from prune_gcc_output to here.
	* lib/prune.exp (prune_gcc_output): Move calls to
	maybe-handle-nn-line-numbers and handle-multiline-outputs from
	here to the above.

Signed-off-by: David Malcolm <dmalcolm@redhat.com>