There are some very large string literals in the compiler tests.
These string literals make the code hard to read,
since you have to scroll down thousands of lines to see the rest of the test case.
Since these strings are very repetitive,
they can be easily generated with a `StringBuilder` and for loops.

After this change,
we will still be testing that ECJ can compile colossal strings,
since there is a test case for that.

Signed-off-by: David Thompson <davthomp@redhat.com>