PR tree-optimization/93247 - ICE in get_load_store_type

PR tree-optimization/93247 - ICE in get_load_store_type

My earlier update_epilogue_loop_vinfo patch introduced an ICE on these
tests for AVX512.  If we use pattern stmts, STMT_VINFO_GATHER_SCATTER_P
is valid for both the original stmt and the pattern stmt, but
STMT_VINFO_MEMORY_ACCESS_TYPE is valid only for the latter.

2020-01-15  Richard Sandiford  <richard.sandiford@arm.com>

gcc/
	PR tree-optimization/93247
	* tree-vect-loop.c (update_epilogue_loop_vinfo): Check the access
	type of the stmt that we're going to vectorize.

gcc/testsuite/
	PR tree-optimization/93247
	* gcc.dg/vect/pr93247-1.c: New test.
	* gcc.dg/vect/pr93247-2.c: Likewise.