testsuite: Add extra aarch64 predefine tests

testsuite: Add extra aarch64 predefine tests

Add extra testing in the following two tests to make sure CPP predefines
redefinitions on #pragma works as expected when -mgeneral-regs-only
option is specified (See PR94678):
gcc.target/aarch64/pragma_cpp_predefs_2.c
gcc.target/aarch64/pragma_cpp_predefs_3.c

2020-04-23  Felix Yang  <felix.yang@huawei.com>

gcc/testsuite/
	PR target/94678
	* gcc.target/aarch64/pragma_cpp_predefs_2.c: Fix typos, pop_pragma ->
	pop_options. Add tests for general-regs-only.
	* gcc.target/aarch64/pragma_cpp_predefs_3.c: Add tests for
	general-regs-only.