LoongArch: Optimize the loading of immediate numbers with the same high and low 32...

LoongArch: Optimize the loading of immediate numbers with the same high and low 32-bit values

For the following immediate load operation in gcc/testsuite/gcc.target/loongarch/imm-load1.c:

	long long r = 0x0101010101010101;

Before this patch:

	lu12i.w	    $r15,16842752>>12
	ori	    $r15,$r15,257
	lu32i.d	    $r15,0x1010100000000>>32
	lu52i.d	    $r15,$r15,0x100000000000000>>52

After this patch:

	lu12i.w     $r15,16842752>>12
	ori         $r15,$r15,257
	bstrins.d   $r15,$r15,63,32

gcc/ChangeLog:

	* config/loongarch/loongarch.cc
	(enum loongarch_load_imm_method): Add new method.
	(loongarch_build_integer): Add relevant implementations for
	new method.
	(loongarch_move_integer): Ditto.

gcc/testsuite/ChangeLog:

	* gcc.target/loongarch/imm-load1.c: Change old check.