gcc.target/i386/pr[27827|50038].c: Compile with -mno-sse

After

commit fb0838bc1073aa5f22ec38e0cca2d70d625c6d71
Author: Richard Biener <rguenther@suse.de>
Date:   Wed Jul 15 10:37:57 2026 +0200

    Support two-lane vector BB reductions without target support

we may vectorize gcc.target/i386/pr27827.c and gcc.target/i386/pr50038.c
with -march=native and

$ make check-gcc RUNTESTFLAGS="--target_board='unix{-m32\ -march=native,-march=native}'

get

FAIL: gcc.target/i386/pr27827.c scan-assembler fmul[ \t]*%st
FAIL: gcc.target/i386/pr50038.c scan-assembler-times movzbl 2

Since these 2 tests don't use SEE instructions originally, compile them
with -mno-sse to avoid test failures.

	PR tree-optimization/126028
	* gcc.target/i386/pr27827.c: Compile with -mno-sse.
	* gcc.target/i386/pr50038.c: Likewise.

Signed-off-by: H.J. Lu <hjl.tools@gmail.com>