testsuite: arm: Only check for absence of literal pools in no-literal-pool-m0.c

testsuite: arm: Only check for absence of literal pools in no-literal-pool-m0.c

With the changes in r15-1579-g792f97b44ff, the constants have been
updated.
This patch drops the fragile check on the constants and instead only
checks that there is no literal pool generated.

gcc/testsuite/ChangeLog:

	* gcc.target/arm/pure-code/no-literal-pool-m0.c: Only check for
	absence of literal pools.

Signed-off-by: Torbjörn SVENSSON <torbjorn.svensson@foss.st.com>