All bytecode text tests are run with stdlib in the classpath and only
for JVM backend, therefore directives WITH_RUNTIME, TARGET_BACKEND,
IGNORE_BACKEND are not needed
DUP_X1; POP = SWAP
p1_a; p1_b; SWAP = p1_b; p1_a
where p1_a, p1_b are instructions without side effects pushing value of
size 1 on stack.
E.g.: ACONST_NULL; ALOAD 0; SWAP = ALOAD 0; ACONST_NULL
NOP; NOP = NOP