Add size check to vector-matrix matmul.

Add size check to vector-matrix matmul.

It turns out the library version is much faster for vector-matrix
multiplications for large sizes than what inlining can produce.
Use size checks for switching between this and inlining for
that case to.

gcc/fortran/ChangeLog:

	* frontend-passes.c (inline_limit_check): Add rank_a
	argument. If a is rank 1, set the second dimension to 1.
	(inline_matmul_assign): Pass rank_a argument to inline_limit_check.
	(call_external_blas): Likewise.

gcc/testsuite/ChangeLog:

	* gfortran.dg/inline_matmul_6.f90: Adjust count for
	  _gfortran_matmul.