testsuite: RISC-V: Skip tests using -mcpu= for ILP32E/ILP64E ABIs

The tests are specifying -mcpu with D extension, which is not compatible
with the ILP32E and ILP64E ABIs.  Fix by skipping the tests if toolchain's
default ABI is an E variant.

gcc/testsuite/ChangeLog:

	* gcc.target/riscv/pr109508.c: Skip for E ABI.
	* gcc.target/riscv/pr114139.c: Ditto.

Signed-off-by: Dimitar Dimitrov <dimitar@dinux.eu>